An Acoustic Analysis of Speech Sounds: a Case Study of the Kokborok Language

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AN ACOUSTIC ANALYSIS OF SPEECH SOUNDS: A CASE STUDY OF THE KOKBOROK LANGUAGE

A Thesis Submitted to the Aligarh Muslim University in partial fulfillment of the requirements for the award of the degree of

DOCTOR OF PHILOSOPHY IN LINGUISTICS

BY FAIJUL HOQUE

Under the Supervision of

Dr. K.S. Mustafa Mohammad Ansari (Supervisor) (Co-supervisor) Professor, Associate Professor, Chairman and BoS Department of Linguistics Centre of Advanced Study in Linguistics Aligarh Muslim University Osmania University Aligarh - 202002 Hyderabad – 500 007

Department of Linguistics Aligarh Muslim University Aligarh (UP) India 2016

ACKNOWLEDGEMENTS

I cannot begin to say how grateful I am to each one of the following for their support and encouragement. Without them, I could never have made it this far……

This work remains in memory of Late Sir Syed Ahmed Khan .

I thank……

My research Supervisors Professor K.S. Mustafa and Mohammad Ansari for their valuable guidance, insights and meticulous editing.

Lieutenant General (rtd) Mr. Zameer Uddin Shah, Vice-Chancellor of Aligarh Muslim University for giving me an opportunity to pursue research in Acoustic Phonetics.

Prof. Sayed Kafeel Ahmad Qasmi, Dean Faculty of arts, AMU, for his moral support.

Prof. Shabana Hameed, Chairman, Department of Linguistics, AMU, for her consistent support and suggestions.

Dr. Nazrin. B. Laskar of the department of Linguistics, AMU, for her advice, encouragement and consistent support at every stage of my work.

My teachers Prof. S.Imtiaz Hasnain, Prof. A.R.Fatihi, Mr. Masood Ali Beg, Dr. Samina A.A. Surti, Dr. Sadia. H. Husain, Dr. Abdul Aziz Khan of the department of Linguistics, AMU.

Prof. Paroo Nihlani who was the inspirational and an integral part of my learning process of acoustic analysis of speech and also choosing the software suitable for my research.

Prof . Shreesh Choudhury of IIT Madras for his apt comments and suggestions.

Mr. Binoy Debbarma, Linguistics officer, TTAADC, Tripura, for granting me permission to collect research materials on Kokborok from the Tribal Research Institute.

All of my informants who readily and patiently let me record all the token of their speech. Without them, this thesis would have been utterly impossible.

Mr. Asad, research scholar, JNU, Mr.Aktar Hussain, research scholar, JMI and Mr. Shamsudheen MK, research scholar, AMU, for their encouragement and consistent support.

Mr. Ali Hussan for his relentless support at every stage of my research and Mr. Antai Kumar Kaipang for his help, support and company at all stage of recording and collection of the data.

Mr. Najeebul Hasan Khan, Seminar incharge and all the office staff of the department of Linguistics, AMU, for their consistent support.

This task would have been incomplete without the unfailing love and support of my parents, my sister and brothers, who helped keep life priorities straight.

All the collaborative efforts made this thesis more than just a part of its sum.

Faijul Hoque

******

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AN ACOUSTIC ANALYSIS OF SPEECH SOUNDS: A CASE STUDY OF THE KOKBOROK LANGUAGE

An Abstract Submitted to the Aligarh Muslim University in partial fulfillment of the requirements for the award of the degree of

DOCTOR OF PHILOSOPHY IN LINGUISTICS

BY FAIJUL HOQUE

Under the Supervision of

Department of Linguistics Aligarh Muslim University Aligarh (UP) India 2016

ABSTRACT

ABSTRACT ______

Kokborok is spoken by more than 15 lakh people in Indian state of Tripura in North East India and the adjacent regions of Bangladesh mainly in Chittagong Hill Tracts. It belongs to Bodo-Garo group of Tibeto- Burman branch of Sino-Tibetan family. The present study is an effort to investigate into the acoustic aspects of the Kokborok speech sounds.

For the acoustic analysis of the Kokborok speech sounds, a list of Kokborok words was prepared and recorded from forty (40) Kokborok speaking informants. They comprise of fifteen (15) men, fifteen (15) women and ten (10) twelve to fifteen years old children (5 boys and 5 girls). The word list prepared for the purpose consisted of sounds in isolation, in words (monosyllabic and polysyllabic) and in simple sentences. The informants were made to record atleast three readings of each word on a digital audio recorder. The first part and the last part of each of the recording were ignored but the middle part was used for the acoustic analysis. The entire speech of every informant and each and every sound articulated by them was phonetically transcribed using IPA.

For the acoustic analysis, speech analysis software called ‘Praat’ was used to generate waveforms as well as spectrograms. The spectrograms and the waveforms were examined very carefully on personal computer (PC) and acoustic analysis of the Kokborok speech sounds was done within the parameters of duration, formant frequency and formant transition. The duration measurements of the Kokborok speech sounds were done in milliseconds. The formant frequencies and formant transitions were measured in hertz. Speech sounds were analysed in terms of numbers and the mean value of the numbers of the sounds were taken and represented graphically.

Abstract

The acoustic analysis of the Kokborok speech sounds in terms of individual speaker variations, gender variations and variations in isolation, different word positions as well as in connected speech was done. Based on this analysis the Kokborok speech sounds were described.

For the sake of convenience, the contents of the whole study are divided into five chapters. The first chapter of the study is ‘Introduction ’. Several aspects are taken up in this chapter. It begins with the introduction and some background notes of the Kokborok language, its speaker and linguistic boundaries. A survey on the Kokborok linguistic and phonetic studies and also a review on the acoustic theory of speech and the acoustic dimensions of speech are presented. The objective here is to test the theory and see whether the precise results come up after the data analysis. The chapter also discusses the aims and objectives, scope, hypotheses, informants’ details, data, methodology and software adopted for the research. As the present study focuses on acoustic analysis of speech sounds, a brief account of the acoustic phonetics and acoustic analytic technique of speech sounds are also discussed.

In the second chapter viz., ‘Phonological Sketch of the Kokborok Language ’ a phonemic analysis of the Kokborok phonemes is done as this analysis is the basis for the acoustic analysis of Kokborok speech sounds. The chapter underscores the need for studying phonemic analysis because there is little information available pertaining to phonemic analysis of sound system of Kokborok till date. For the sake of convenience, this chapter is divided into two parts. Part one deals with the Kokborok vowels. This part presents a phonemic inventory of vowels of Kokborok. The phonemic inventory shows that the Kokborok language has the eight (8) phonetically distinctive vowel phonemes, four (4) phonologically distinctive diphthongs and a triphthong. The following table lists the Kokborok vowels, diphthongs and triphthong.

Abstract

Table . The Kokborok vowel phonemes.

This part also gives the classification, description, distribution of each vowel phoneme and also shows contrast between them. Further it also presents spectrographic sketches of all the Kokborok vowel phonemes and describes each one of them on the basis of the acoustic cues. The eight vowel phonemes and four diphthongs and a triphthong exist in word initial, medial and final positions except the vowel /ə/ and /o/ . The vowel /ə/ occurs only in word medial position. The vowel /o/ occurs only in word medial and final positions. All the eight Kokborok vowels have the contrast in word initial, medial and final positions except the vowel /ə/ and /o/ . The vowel /ə/ shows contrast only in medial position. The vowel /o/ exhibits contrast only in word medial and final positions.

Part two deals with the Kokborok consonants phonemes. It presents a phonemic inventory of consonants of Kokborok. The phonemic inventory shows that the Kokborok language has nineteen (19) consonant phonemes. They are articulated from five (5) different places of articulation: bilabial, alveolar, palatal, velar and glottal and from four (4) different manners of articulation: stop, fricative, nasal and approximant. The following table lists the Kokborok consonants.

Abstract

Labial Coronal Dorsal Places of articulation → Glottal Bilabial Alveolar Palatal Velar Manners of articulation ↓ Unaspirated p t k Voiceless Aspirated ph th čh kh Stops

Voiced Unaspirated b d ǰ ɡ

Obstruents

Fricatives Voiceless s h

Nasals Voiced m n ŋ

Lateral l Approxi Voiced

Sonorants Sonorants mants Central r j

Table . The Kokborok consonant phonemes.

The study classifies the Kokborok stops into three sets: (i) the voiceless unaspirated stops, (ii) the voiceless aspirated stops and (iii) the voiced stops. The voiceless unaspirated stops have aspirated counterparts but voiced aspirated counterparts are non-existent in Kokborok. The voiceless palatal aspirated stop - /čh/ has no unaspirated counterpart in the language. All the nineteen consonant phonemes occur in word initial, medial and final positions except the aspirated stop consonants [/ ph, th, čh, kh /] and the consonants [/b, d, ǰ, ŋ and j /]. The occurrence of consonant phonemes [/ ph, th, čh, kh /] and [/ b, d, ǰ, j, /] is limited to the word initial and medial positions. However the phoneme / ŋ/ occurs in the word medial and final positions. All the Kokborok homorganic and heterorganic consonant phonemes show contrast in word medial position but a few have contrast in the initial position and still a few have contrast in the word final position. It also gives the classification, description, distribution of each phoneme. Further it also presents spectrographic sketches of all the Kokborok consonant phonemes and describes each phoneme on the basis of the acoustic cues.

Abstract

The third chapter viz., ‘ Acoustic Analysis of the Kokborok Vowels ’ deals with the Kokborok vowels phonemes. For the sake of convenience, the chapter is divided into two parts. Part one deals with the acoustic analysis of the Kokborok monophthongs and part two with the acoustic analysis of the Kokborok diphthongs and triphthong. Both the parts of this chapter give a numerical analysis of the Kokborok vowels – monophthongs, diphthongs and triphthong. The numerical analysis of the Kokborok vowels is done in terms of duration, formant frequency and transition. The chapter also deals with the individual variations and gender variations in terms of duration, formant frequency and transition.

The numerical analysis shows that the duration of all the Kokborok vowels whether produced in isolation or in words or connected speech by men, women or children differ from one another on the basis of individual speaker, his or her gender and age group. It is also seen that sounds articulated in connected speech take the shortest duration, sounds articulated in words take longer duration and sounds articulated in isolation take the longest duration. The variations of vowels in terms of their speakers come up in such a way that men have the shortest duration; children have longer duration and women have the longest duration. It also shows that the Kokborok low vowel has longer duration than the high vowels.

The numerical analysis confirms the view that the Kokborok front vowels have high f 2 but back vowels have low f 2. Further, f1 and f 2 are far apart in front vowels but f 2 and f 3 are close together. The f 1 and f 2 are close together in back vowels but f 2 and f 3 are far apart. It is also noted that for central vowel f1, f2 and f 3 frequencies are at equidistance.

The acoustic measurements of the Kokborok vowels also confirms that the ‘vowel height’ which corresponds to the ‘tongue height’, (i.e. for high and

Abstract low vowels) in respect of children is the lowest; for women it is higher and for men is the highest when the vowels are produced in isolation, in words or connected speech.

The acoustic measurement of the study finds that all the Kokborok vowel phonemes whether produced in isolation, in words or in connected speech either by men, women or children are varied from one another in their duration and formant frequency range. The average duration and formant frequency range of the Kokborok vowel phonemes in the vocal tract is as follows: Duration range Formant frequency range Vowels Formant (in between) (in between) f1 253 Hz – 449 Hz i 86 m.sec – 311 m.sec f2 2243 Hz – 2701 Hz f3 3005 Hz – 3437 Hz f1 479 Hz – 674 Hz e 67 m.sec – 337 m.sec f2 2078 Hz – 2531 Hz f3 2707 Hz – 3191 Hz f1 609 Hz – 784 Hz a 156 m.sec – 357 m.sec f2 1655 Hz – 2070 Hz f3 2407 Hz – 2957 Hz f1 466 Hz – 679 Hz ə 53 m.sec – 195 m.sec f2 1469 Hz – 1827 Hz f3 2567 Hz – 2919 Hz f1 281 Hz – 507 Hz ɯ 81 m.sec – 332 m.sec f2 1128 Hz – 1557 Hz f3 2410 Hz – 2776 Hz f1 563 Hz – 764 Hz ɔ 105 m.sec – 339 m.sec f2 865 Hz – 1233 Hz f3 2364 Hz – 2832 Hz f1 451 Hz – 659 Hz o 144 m.sec – 335 m.sec f2 780 Hz – 1108 Hz f3 2244 Hz – 2876 Hz f1 248 Hz – 450 Hz u 84 m.sec – 321 m.sec f2 608 Hz – 1035 Hz f3 2322 Hz – 2691 Hz Table . Duration and formant frequency range of the Kokborok vowels

Abstract

The fourth chapter viz., ‘ Acoustic Analysis of the Kokborok Consonants ’ deals with the Kokborok consonants. For the sake of convenience, the chapter is divided into two parts. Part one deals with the acoustic analysis of the Kokborok obstruents and part two with the acoustic analysis of the Kokborok sonorants. Both the parts of this chapter give a numerical analysis of the Kokborok obstruents and sonorants. Like vowels, the acoustic analysis of the Kokborok consonants is done in terms of duration, formant frequency and formant transition. The chapter also gives the individual variations and gender variations in terms of duration, formant frequency and formant transition.

The numerical analysis of the Kokborok consonants phonemes shows that the duration of all the Kokborok consonants whether produced in monosyllabic words, polysyllabic words or connected speech either by men, women or children is varied from each other because of individual and gender differences. The results of the duration measurements of the Kokborok consonant phonemes show that that men take the lowest duration, children take higher duration and women take the highest duration.

In terms of place articulation it is noted that the labial stops have the longest closure duration, coronal stops have shorter closure duration and dorsal stops have the shortest closure duration. In terms of voice quality, (i.e. for voiced and voicelessness) it is noted that the voiceless stops have longer closure duration in comparison to their voiced counterpart. In terms of aspiration and unaspiration it is noted that the unaspirated stops have longer closure duration than their aspirated counterpart.

In terms of place articulation it is observed that the labial stops have the shortest VOT, coronal stops have longer VOT and dorsal stops have the longest VOT. In terms of aspiration and unaspiration it is observed that the voiceless unaspirated stops have shorter VOT than the voiceless aspirated

Abstract stops. In terms of voice quality it is seen that the voiceless unaspirated stops have shorter VOT than their voiced counterparts i.e. voiced unaspirated stops.

The study confirms that the relationship in terms of place of articulation, voice quality and aspiration and unaspiration, between closure duration and VOT is inversely proportional i.e. the closure duration decreases as the VOT increases and vice versa.

The coronal fricative /s/ takes longer frication duration than glottal fricative /h/ . In terms of place of articulation, the labial nasal /m/ takes the longest murmur duration, the coronal nasal /n/ takes shorter murmur duration and the dorso-velar nasal /ŋ/ takes the shortest murmur duration. In terms of place of articulation, the alveolar lateral approximant /l/ takes the shortest duration, the palatal central approximant /j/ takes longer duration and the alveolar central approximant /r/ takes the longest duration.

The acoustic measurement of the study finds that all the Kokborok consonant phonemes whether produced in isolation, in words or in connected speech either by men, women or children are varied from one another in their duration, formant frequency and formant transition range. According to the manner of articulation the average duration, formant frequency and formant transition range of the Kokborok consonant phonemes in the vocal tract is given below:

Abstract

Formant frequency range for voiced Duration range sounds and formant Speech sounds Formant (in between) transition range for voiceless sounds (in between)

p 99 m.sec – 178 m.sec f1, f 2 and f 3 854 Hz – 3621 Hz h Labial stops p 93 m.sec – 169 m.sec f1, f 2 and f 3 717 Hz - 3680 Hz

b 75 m.sec – 138 m.sec f1, f 2 and f 3 476 Hz – 3914 Hz t 95 m.sec – 166 m.sec f1, f 2 and f 3 710 Hz – 3507 Hz h Coronal stops t 89 m.sec – 143 m.sec f1, f 2 and f 3 602 Hz – 2594 Hz d 69 m.sec – 132 m.sec f1, f 2 and f 3 446 Hz – 3764 Hz h Dorso-palatal č 82 m.sec – 127 m.sec f1, f 2 and f 3 674 Hz - 3607 Hz stops ǰ 65 m.sec – 125 m.sec f1, f 2 and f 3 416 Hz – 3070 Hz

k 87 m.sec – 147 m.sec f1, f 2 and f 3 785 Hz – 3470 Hz Dorso-velar h k 79 m.sec – 119 m.sec f1, f 2 and f 3 618 Hz – 3689 Hz stops ɡ 57 m.sec – 123 m.sec f1, f 2 and f 3 401 Hz – 3751 Hz s 103 m.sec – 185 m.sec f , f and f 1421 Hz – 3506 Hz Fricatives 1 2 3 h 77 m.sec – 168 m.sec f1, f 2 and f 3 909 Hz – 2002 Hz m 58 m.sec – 107 m.sec f1, f 2 and f 3 270 Hz – 2852 Hz Nasals n 55 m.sec – 101 m.sec f1, f 2 and f 3 295 Hz – 2928 Hz ŋ 53 m.sec – 94 m.sec f1, f 2 and f 3 331 Hz –2966 Hz

r 89 m.sec – 231 m.sec f1, f 2 and f 3 258 Hz - 2502 Hz Approximants l 55 m.sec – 163 m.sec f1, f 2 and f 3 315 Hz – 2803 Hz j 77 m.sec – 212 m.sec f1, f 2 and f 3 298 Hz – 2742 Hz Table . Formant frequency and formant transition range of the Kokborok consonants

The fifth chapter viz., ‘ Conclusions ’ is the final chapter. It presents researcher’s conclusions of the study he has done with respect to acoustic analysis of the Kokborok speech sounds. Further it briefly gives the significance of the study and hints at further studies that could be undertaken with respect to the Kokborok language.

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CONTENTS Page

Chapter 1 : Introduction 1-41 1.0 Overview 3 1.1 Kokborok: An Introduction 3 1.2 Kokborok and the Borok 3 1.3 Kokborok and its Dialects 4 1.4 Kokborok: A brief historical note 6 1.5 Kokborok speakers and its linguistic boundaries 6 1.6 Genetic classification of Kokborok and its place among Modern Tibeto-Burman languages 8 1.7 Kokborok: Script and Orthography 11 1.8 The present Status of Kokborok 12 1.9 Literature Review 14 1.9.1 Studies done on Kokborok 14 1.10 Theoretical Basis 19 1.10.1 The Acoustic Phonetics 19 1.10.2 Acoustics of Speech Production 20 1.10.3 Acoustic Theory of Speech Production 21 1.10.4 Standing Waves and Resonance Theory 22 1.10.5 Sound Sources in the Vocal Tract 23 1.10.6 Vocal Tract Resonance / Tube Models 24 1.10.7 Perturbation Theory of Speech Production 25 1.11 The Acoustic Dimension of Speech Sounds 26 1.12 Duration of Speech Sounds 26 1.12.1 Voice Onset Time (VOT) 27

1.13 Fundamental frequency (f 0) of Speech Sounds 29 1.14 Formant Frequency of Speech Sounds 30 1.14.1 Formant Transition of Speech Sounds 31

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1.15 Digitisation of Speech Wave 31 1.15.1 Spectrogram 31 1.15.2 Narrow Band Spectrogram 32 1.15.3 Wide/Broad Band Spectrogram 33 1.16 Description of Acoustic Cues 33 1.17 The Scope of the Study 34 1.18 The Aims of the Study 35 1.19 The Objectives of the study 35 1.20 The Hypothesis of the Study 35 1.21 The Informants 36 1.22 The Data 37 1.23 The Methodology of the Research 38 1.24 The Acoustic Analytic Techniques 40 1.25 The Parameters of Acoustic Analysis of Speech Sounds 40 1.26 Thesis outline 41

Chapter 2 : Phonological Sketch of the Kokborok Language 43-83 2.0 Overview 45 Part I : Vowels 45 2.1.1 Introduction 45 2.1.2 Phonemic Inventory of the Kokborok vowels 46 2.1.3 Description, classification and phonemic Analysis of the 48 Kokborok vowels 2.1.4 The first parametric classification of the Kokborok 48 vowels 2.1.4.1 The front vowels in Kokborok 48 2.1.4.2 The central vowels in Kokborok 49 2.1.4.3 The Back vowels in Kokborok 50 2.1.5 The second parametric classification of the Kokborok 52 vowels 2.1.6 The spectrographic sketch of the Kokborok vowels 54

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2.1.7 The formant frequency values of the Kokborok 55 vowels 2.1.8 The Kokborok vowel quadrilateral 57 2.1.9 The Kokborok Diphthongs 58 2.1.10 The Kokborok Triphthong 62 Part II: Consonants 64 2.2.1 Introduction 64 2.2.2 Phonemic inventory of the Kokborok consonants 64 2.2.3 Classification of the Kokborok consonants 65 2.2.3.1 The Voiceless Unaspirated Stops 66 2.2.3.2 The Voiceless Aspirated Stops 67 2.2.3.3 The Kokborok Voiced Stops 69 2.2.3.4 The Kokborok Fricatives 72 2.2.3.5 The Kokborok Nasals 74 2.2.3.6 The Kokborok Approximants 76 2.2.4 The contrast in Kokborok phonemes 78 2.2.5 The articulatory sources of the Kokborok speech 80 sounds 2.2.6 Tones in Kokborok 82 2.2.7 Findings 82

Chapter 3 : Acoustic Analysis of the Kokborok Vowels 85-122 3.0 Overview 87 Part I : Vowels 87 3.1.1 Introduction 87 3.1.2 Method 88 3.1.2.1 Participants 88 3.1.2.2 Stimuli 88 3.1.2.3 Procedure 88

3.1.3 Results and discussion 89 3.1.3.1 Duration measurement of the Kokborok 89 vowels 3.1.3.2 Formant frequency measurement of the Kokborok vowels 95

Part II : Diphthongs and Triphthong 110 3.2.1 Results and discussion 110 3.2.1.1 Duration measurement of the Kokborok Diphthongs and Triphthong 110 3.2.1.2 Formant frequency measurement of the 112 Kokborok Diphthongs 3.2.1.3 Formant frequency measurement of the 117 Kokborok Triphthong 3.2.2 Findings 120

Chapter 4 : Acoustic Analysis of the Kokborok Consonants 123-192 4.0 Overview 125 Part I : Obstruents 125 4.1.1 Introduction 125 4.1.2 Method 125 4.1.2.1 Participants 126 4.1.2.2 Stimuli 126 4.1.2.3 Procedure 126 4.1.3 Results and discussions 126 4.1.3.1 Closure Duration measurement of the 127 Kokborok Stops 4.1.3.2 Voice Onset Time (VOT) measurement of the 135 Kokborok Stops 4.1.3.3 Formant transition measurement of the last glottal pulse leading to the Kokborok Voiceless 142 stops 4.1.3.4 Formant frequency measurement of the 148 Kokborok voiced Stops 4.1.3.5 Noise duration or frication duration measurement of the Kokborok Fricatives 155

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4.1.3.6 Formant transition measurement of the last glottal pulse leading to the Kokborok Fricatives 159

Part II : Sonorants 162 4.2.1 Results and discussions 162 4.2.1.1 Closure or murmur Duration measurement of the Kokborok Nasals 162 4.2.1.2 Formant frequency measurement of the Kokborok Nasals 166 4.2.1.3 Duration measurement of the Kokborok 175 Approximants 4.2.1.4 Formant frequency measurement of the 179 Kokborok Approximants 4.2.2 Findings 186

Chapter 5 : Conclusions 193 5.1 Significance and contributions of the study 196 5.2 Suggestions for further research 197

References 199-219

Appendix 221-267 Appendix – 1 Sample Data of the Kokborok Speech 223 Sounds Appendix – 2 Sample Spectrograms 224 Appendix – 3 Sample Data Analysis Table 262 Appendix – 4 Sample Calculation of Anti-formant 263 Appendix – 5 Sample Photo Album 264

Publications 268

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LIST OF TABLES Page

1. Table 1.21 The list of informants. 36 2. Table 1.22 (a) The list of the Kokborok Vowels. 37 3. Table 1.22 (b) The list of the Kokborok Consonants. 38 4. Table 2.1.2 The Kokborok vowel phonemes. 47 5. Table. 2.1.4.1 (a) Examples of the occurrence of phoneme /i/. 49 6. Table. 2.1.4.1 (b) Examples of the occurrence of phoneme /e/. 49 7. Table. 2.1.4.2 (a) Examples of the occurrence of phoneme /a/. 50 8. Table. 2.1.4.2 (b) Examples of the occurrence of phoneme / ə/. 50 9. Table. 2.1.4.3 (a) Examples of the occurrence of phoneme / ɯ/. 51 10. Table. 2.1.4.3 (b) Examples of the occurrence of phoneme / ɔ/. 51 11. Table. 2.1.4.3 (c) Examples of the occurrence of phoneme /o/. 51 12. Table. 2.1.4.3 (d) Examples of the occurrence of phoneme /u/. 52 13. Table: 2.1.5 (a) Contrast in word initial position. 53 14. Table: 2.1.5 (b) Contrast in word medial position. 53 15. Table: 2.1.5 (c) Contrast in word final position. 54 16. Table 2.1.7 Frequency (in Hz) values of f and f of the 1 2 56 Kokborok Vowels. 17. Table. 2.1.9 (a) Examples of the occurrence of diphthong /ai/. 60 18. Table. 2.1.9 (b) Examples of the occurrence of diphthong / ɔi/. 60 19. Table. 2.1.9 (c) Examples of the occurrence of diphthong /au/. 61 20. Table. 2.1.9 (d) Examples of the occurrence of diphthong /ua/. 61 21 Table. 2.1.10 Examples of the occurrence of triphthong /uai/. 63 22. Table 2.2.2 The Kokborok consonant phonemes. 65 23. Table 2.2.3.1 The Kokborok voiceless unaspirated stops. 66 24. Table. 2.2.3.1 Examples of the occurrence of Kokborok voiceless 67 unaspirated stops {/p, t, k/}. 25. Table 2.2.3.2 The Kokborok voiceless aspirated stops. 67 26. Table. 2.2.3.2 Examples of the occurrence of Kokborok voiceless 69 aspirated stops {/p h, t h, čh, k h/}. 27. Table 2.2.3.3 Kokborok voiced stops. 69 28. Table. 2.2.3.3 Examples of the occurrence of Kokborok voiced 72 stops {/b, d, ǰ, ɡ/}.

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29. Table 2.2.3.4 The Kokborok fricatives. 72 30. Table. 2.2.3.4 Examples of the occurrence of Kokborok fricatives 74 {/s, h/}. 31 Table 2.2.3.5 The Kokborok Nasals. 74 32. Table. 2.2.3.5 Examples of the occurrence of Kokborok nasals 76 {/m, n, ŋ/}. 33. Table 2.2.3.6 The Kokborok approximants. 76 34. Table. 2.2.3.6 Examples of the occurrence of Kokborok 78 approximants {/r, l, j/}. 35. Table. 2.2.4 The sets of Kokborok homorganic sounds. 78 36. Table: 2.2.4 (a) Contrast in initial, medial and final positions. 79 37. Table: 2.2.4 (b) Contrast in initial, medial and final positions. 80 38. Table 2.2.5 The Kokborok speech sound sources. 81 39. Table 2.2.6 Examples of Kokborok Tones. 82 40. Table 3.1.3.1 Average duration values and the percentage of 90 duration of the Kokborok vowels. 41. Table 3.1.3.2 (a) Average formant frequency values and the negative formant frequency values of the Kokborok vowels in 96 isolation. 42. Table 3.1.3.2 (b) Average formant frequency values and the negative formant frequency values of the Kokborok vowels in 97 words. 43. Table 3.1.3.2 (c) Average formant frequency values and the negative formant frequency values of the Kokborok vowels in 98 connected speech. 44. Table 3.2.1.1 Average duration values of the Kokborok 111 diphthongs and triphthong. 45. Table 3.2.1.2 Average formant frequency values of the onglide and offglide of the Kokborok diphthongs, together 113 with the negative values of average formant frequencies. 46. Table 3.2.1.3 Average formant frequency values of the onglide, mid and offglide of the Kokborok triphthong, 118 together with the negative values of average formant frequencies. 47. Table 4.1.3.1 (a) Average closure duration and VOT values of the Kokborok Stops in monosyllabic words and the duration of overall utterance and the percentage of 128 closure duration and VOT within the overall utterance.

48. Table 4.1.3.1 (b) Average closure duration and VOT values of the Kokborok stops in polysyllabic words and the duration of overall utterance and the percentage of 129 closure duration and VOT within the overall utterance. 49. Table 4.1.3.1 (c) Average closure duration and VOT values of the Kokborok stops in connected speech and the duration of overall utterance and the percentage of 130 closure duration and VOT within the overall utterance. 50. Table 4.1.3.3 Average formant transition values of the last glottal 143 pulse leading to the Kokborok voiceless stops. 51. Table 4.1.3.4 Average formant frequency values of the Kokborok 149 voiced stops. 52. Table 4.1.3.5 Average frication duration and percentage of 156 frication values of the Kokborok Fricatives. 53. Table 4.1.3.6 Average formant transition values of the last 159 glottal pulse leading to the Kokborok fricatives. 54. Table 4.2.1.1 Average closure or murmur duration values of the 163 Kokborok Nasals. 55. Table 4.2.1.2 Average formant frequency values of the Kokborok nasals in monosyllabic words, polysyllabic words 167 and in connected speech. 56. Table 4.2.1.3 Average duration values of the Kokborok 176 approximants. 57. Table 4.2.1.4 Average formant frequency values of the Kokborok approximants in monosyllabic words, polysyllabic 179 words and connected speech.

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LIST OF FIGURES Page

0 Map The existing linguistic boundaries of the Kokborok. 7 1. Figure 1.6 (a) The schematic representation of Scott Delancey’s 9 “The Modern Tibeto- Burman language family”. 2. Figure: 1.6 (b) Bodo-Garo Language group. 10 3. Figure: 1.6 (c) Position of Kokborok among the modern Tibeto- 11 Burman languages. 4. Figure 1.10.3 Source Filter of Speech Sounds. 22 5. Figure 1.10.7 The locations for f 1, f 2, and f3 in the vocal tract. 26 6. Figure 1.12.1 Waveform and spectrogram shows VOT in the words 28 /apa/ (father) and /ap ha/ (my father). 7. Figure 1.16 Waveform and spectrogram of the word /sak čha/ 34 (selfish). 8. Figure 2.1.6 Waveforms and spectrograms of the Kokborok eight 55 (8) vowels. 9. Figure 2.1.7 The formant frequency values of f and f of the 1 2 56 Kokborok vowels and their positions. 10. Figure 2.1.8 The vowel quadrilateral showing the formant frequency values (in Hz) of f 1 and f 2 of the Kokborok 58 vowels. 11. Figure 2.1.9 Waveforms and spectrograms of the Kokborok four 59 (4) diphthongs. 12. Figure 2.1.10 Waveform and spectrogram of the Kokborok 62 triphthong. 13. Figure 2.2.3.1 Waveforms and spectrograms of the Kokborok 66 voiceless unaspirated stops in /apa/, /ata/ and /akar/. 14. Figure 2.2.3.2 Waveforms and spectrograms of the Kokborok voiceless aspirated stops in /ap ha/, /at haŋ/, /ka čha/ and 68 /ak hata/. 15. Figure 2.2.3.3 Waveforms and spectrograms of the Kokborok voiced 71 stops in /haba/, /hada/, /ra ǰa/ and /a ɡar/. 16. Figure 2.2.3.4 Waveforms and spectrograms of the Kokborok 73 fricatives in /kasa/ and /kaham/. 17. Figure 2.2.3.5 Waveforms and spectrograms of the Kokborok 75 nasals in /lama/, /lana/ and /la ŋa/. 18. Figure 2.2.3.6 Waveforms and spectrograms of the Kokborok 77 approximants in /kara/, /kalam/ and /aja ŋ/.

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19. Figure 3.1.3.1 (a) Average duration values of the Kokborok vowels produced by men in isolation (Blue Colum), in a 91 word (Red Colum) and connected speech (Green Colum). 20. Figure 3.1.3.1 (b) Average duration values of the Kokborok vowels produced by women in isolation (Blue Colum), in 91 a word (Red Colum) and connected speech (Green Colum). 21 Figure 3.1.3.1 (c) Average duration values of the Kokborok vowels produced by children in isolation (Blue Colum), in 92 a word (Red Colum) and connected speech (Green Colum). 22. Figure 3.1.3.1 (d) Average duration values of the Kokborok vowels in words produced by men (Blue Colum), women 93 (Red Colum) and children (Green Colum). 23. Figure 3.1.3.1 (e) Percentage of vowel duration for men (Blue Colum), women (Red Colum) and children (Green 94 Colum) within words and connected speech. 24. Figure 3.1.3.2 (a) Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by men in isolation 99 (black lines), in words (red lines) and connected speech (green lines). 25. Figure 3.1.3.2 (b) Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by women in isolation 100 (black lines), in words (red lines) and connected speech (green lines). 26. Figure 3.1.3.2 (c) Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by children in 101 isolation (black lines), in words (red lines) and connected speech (green lines). 27. Figure 3.1.3.2 (d) Average formant frequency values of the first three formants and the positioning of the Kokborok vowels in words produced by men 102 (black lines), women (red lines) and children (green lines). 28. Figure 3.1.3.2 (e) Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by men in 104 isolation (black line), in words (red line) and connected speech (green line).

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29. Figure 3.1.3.2 (f) Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by women in isolation 105 (black line) in words (red line) and connected speech (green line). 30. Figure 3.1.3.2 (g) Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by children in 106 isolation (black line), in words (red line) and connected speech (green line). 31 Figure 3.1.3.2 (h) Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels in words produced by men (bold 108 dot), women (rectangular) and children (triangular). 32. Figure 3.2.1.1 Average duration values of the Kokborok diphthongs and triphthong in words produced by 112 men (Blue Colum), women (Red Colum) and children (Green Colum). 33. Figure 3.2.1.2 (a) Acoustic diagram showing the positioning of average formant frequency values of the onglide 114 and offglide of the Kokborok diphthongs in respect of men. 34. Figure 3.2.1.2 (b) Acoustic diagram showing the positioning of average formant frequency values of the onglide 115 and offglide of the Kokborok diphthongs in respect of women. 35. Figure 3.2.1.2 (c) Acoustic diagram showing the positioning of average formant frequency values of the onglide 115 and offglide of the Kokborok diphthongs in respect of children. 36. Figure 3.2.1.3 Acoustic diagram showing the positioning of average formant frequency values of the onglide, 119 mid and offglide of the Kokborok triphthong in respect of men, women and children. 37. Figures 4.1.3.1 (a) Average closure duration values of the Kokborok stops produced by men in monosyllabic words 131 (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 38. Figures 4.1.3.1 (b) Average closure duration values of the Kokborok stops produced by women in monosyllabic words (Red Colum), polysyllabic words (Green Colum) 132 and in connected speech (Blue Colum).

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39. Figures 4.1.3.1 (c) Average closure duration values of the Kokborok stops produced by children in monosyllabic words 132 (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 40. Figures 4.1.3.1 (d) Average closure duration values of the Kokborok stops in polysyllabic words, produced by men 134 (Red Colum), women (Green Colum) and children (Blue Colum). 41. Figure 4.1.3.1 (e) Percentage of closure duration within the overall utterance produced by men in monosyllabic words 135 (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 42. Figures 4.1.3.2 (a) Average VOT values of the Kokborok stops produced by men in monosyllabic words (Red 136 Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 43. Figures 4.1.3.2 (b) Average VOT values of the Kokborok stops produced by women in monosyllabic words (Red 137 Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 44. Figures 4.1.3.2 (c) Average VOT values of the Kokborok stops produced by children in monosyllabic words (Red 137 Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 45. Figures 4.1.3.2 (d) Average VOT values of the Kokborok stops in polysyllabic words, produced by men (Red 139 Colum), women (Green Colum) and children (Blue Colum). 46. Figure 4.1.3.2 (e) Percentage of VOT within the overall utterances produced by men in monosyllabic words (Red 140 Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 47. Figure 4.1.3.2 (f) Average closure duration + VOT values of Kokborok stops in polysyllabic words, produced 141 by men, women and children. 48. Figure 4.1.3.3 The diagram showing average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops (in Hz) of f 1 (blue line), 144 f2 (red line) and f 3 (green line) in a word produced by men, women and children. 49. Figure 4.1.3.4 The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok voiced stops produced in polysyllabic 150 words by men (black dot), women (red rectangle) and children (green triangle).

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50. Figures 4.1.3.5 (a) Average noise duration values of the Kokborok fricatives produced by men, women and children in monosyllabic words (Red Colum), polysyllabic 157 words (Green Colum) and in connected speech (Blue Colum). 51. Figure 4.1.3.5 (b) Percentage of noise duration in the overall utterances produced by men, women and children in monosyllabic words (Red Colum), polysyllabic 158 words (Green Colum) and in connected speech (Blue Colum). 52. Figure 4.1.3.6 The diagram showing average formant transition values of the last glottal pulse leading to the Kokborok fricatives (in Hz) of f 1 (blue line), f 2 160 (red line) and f 3 (green line) in a word produced by men, women and children. 53. Figures 4.2.1.1 (a) Average closure or murmur duration values of the Kokborok Nasals produced by men, women and children in monosyllabic words 164 (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 54. Figure 4.2.1.1 (b) Percentage of closure duration within the overall utterances produced by men, women and children in monosyllabic words (Red Colum), polysyllabic 165 words (Green Colum) and in connected speech (Blue Colum). 55. Figure 4.2.1.2 (a) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by men in 168 monosyllabic words (black dot), polysyllabic words (red rectangle) and in connected speech (green triangle). 56. Figure 4.2.1.2 (b) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by women in 168 monosyllabic words (black dot), polysyllabic words (red rectangle) and in connected speech (green triangle). 57. Figure 4.2.1.2 (c) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by children in monosyllabic words (black dot), polysyllabic 169 words (red rectangle) and in connected speech (green triangle).

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58. Figure 4.2.1.2 (d) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced in polysyllabic words 169 by men (black dot), women (red rectangle) and children (green triangle). 59. Figure 4.2.1.2 (e) The diagram showing average formant frequency (red Colum) and anti-formant (green Colum) 174 values (in Hz) of f 1 and f 2 of the Kokborok nasals. 60. Figure 4.2.1.3 (a) Average duration values of the Kokborok approximants produced by men, women and children in monosyllabic words (Red Colum), 177 polysyllabic words (Green Colum) and connected speech (Blue Colum). 61. Figure 4.2.1.3 (b) Percentage of approximants duration within the overall utterances produced by men, women and children in monosyllabic words (Red Colum), 178 polysyllabic words (Green Colum) and connected speech (Blue Colum). 62. Figure 4.2.1.4 (a) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by men 180 in monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle). 63. Figure 4.2.1.4 (b) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by 181 women in monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle). 64. Figure 4.2.1.4 (c) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by children in 181 monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle). 65. Figure 4.2.1.4 (d) The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced in 182 polysyllabic words by men (black dot), women (red rectangle) and children (green triangle).

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ACRONYMS ______

(A) LIST OF AB BREVIATIONS

M Man W Woman C Children f0 fundamental frequency f1 first formant f2 second formant f3 third formant RB Release Burst Asp Aspiration IPA International Phonetic A lphabet VOT Voice Onset Time LPC Linear Predictive Coding PC Personal Computer Hz Hertz m.sec millisecond S.I Sound in Isolation S.W Sound in Word S.MW Sound in Monosyllabic Word S.PW Sound in Polysyllabic Word S.CS Sound in Connected Speech Mns Minus i.e. that is e.g. for example viz namely etc etcetera SL Serial RD Rounded UD Unrounded

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(B) LIST OF NOTATIONAL CONVENTIONS

Hyphen - Oblique / Comma , Inverted Commas “ ” Semi inverted commas ‘ ’ Semi colon ; Colon : Full stop . Phonemic writing/Transcription / / Square Brackets [ ] Curly Brackets { } Less Than < Greater Than > Brackets ( ) Percentage % The Arrow → Circle

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Chapter 1 : Introduction ______

1.0 Overview Before embarking on the acoustic analysis of the Kokborok speech sounds, an attempt is made in this chapter to present some background notes on issues such as: introduction to the language and its speakers, its different dialects, a brief historical account of the language, its linguistics boundaries. The chapter will also deal with Kokborok’s genetic classification and its place among modern Tibeto-Burman languages, its script and orthography, its present status, literature review, theoretical background, aims and objectives, scope, hypotheses, informants, data, methodology of the research, thesis outline.

1.1 Kokborok: An Introduction Kokborok is the language spoken in Indian state of Tripura in North East India and also in the adjacent regions of Bangladesh mainly Chittagong Hill Tracts. It belongs to Bodo-Garo group of Tibeto-Burman branch of Sino- Tibetan family. The term ‘Kokborok’ in fact is a compound of two main words viz; ‘Kok’ which literally means ‘language’ and ‘Borok’ means ‘human being’. However, interestingly the second word is used to denote the Borok people who belong to Tripura. Therefore, in literal terms Kokborok means ‘Language of human being’. However, in actuality it means a language spoken by the native tribal communities of Tripura.

1.2 Kokborok and the Borok People speaking Kokborok are known as Borok. The Borok comprises of eight (8) major tribal communities having similar culture and life style. They are also recognized as the Borok race. These tribal communities are

3 Chapter 1: Introduction

Tripuri, Reang, Jamatia, Noatia, Murasing, Koloi, Rupini and Uchoi . They are the aboriginal tribes of Tripura. Ethnically, they are Mongoloids and it is evident from their physical appearance. Briefly speaking, the Mongoloids are of fair complexion, broad head, flat nose, medium to tall height and have small eyes and thick ankles. The ethnic characteristics of these tribes are gradually changing in the state because of inter marriage with many other tribes and castes.

1.3 Kokborok and its Dialects Kokborok has eight (8) major dialects and each of these dialects has been named after a particular tribe. These dialects are:

1. Debbarma (Puran Tripuri), 2. Reang (Bru), 3.Jamatia, 4.Noatia (New Tripuri), 5. Murasing, 6.Uchoi, 7.Koloi and 8.Rupini. Speakers of all these dialects are scattered all over the state of Tripura. An outline of each dialect area is in the following: (1) Debbarma (Puran Tripuri): Speakers of Debbarma (Puran Tripuri) dialect is Debbarma or Debbarman community. This dialect is spoken by the members of the Tripura Royal Family and their close relatives living in Agartala, the capital of Tripura. They use Debbarma as their Surname. Speakers of this dialect are living both in towns and in hills. This dialect covers areas of Sadar sub-divisions (both North and South) of the West Tripura District. Some speakers belonging to this community also live in Khowai, Kamalpur, Kailashahar, Dharmanagar and Longtarai valley sub- divisions. This is a dominant dialect, which in fact represents Kokborok. 2. Reang (Bru): This dialect covers areas of both south and North Tripura Districts. In south, the remarkable areas inhabited by the Reangs include Kasima, Kurma, Chelagang, Durgarampara, Satyarampara, and Karbook. In North, the Reang speaking people live in the subdivisions of Kailashahar,

Chapter 1: Introduction

Dharmanagar, Kanchanpur, and the Jumpui Hills. This is the second major dialect of Kokborok. 3. Jamatia: This dialect covers the area of the sub-divisions of Udaipur, Amarpur and Gandachera. The oldest village having Jamatia dialect is Pitra near Udaipur, from where the people speaking this prestigious dialect of Kokborok spread all over Udaipur and Amarpur. The compact area of this dialect more or less has been maintained. 4. Noatia (New Tripuri): The dialect is spoken in the areas spread over the sub-divisions of Sonamura, Belonia, Santirbazar and Sabroom. 5. Murasing: This dialect falls under the sub-divisions of Belonia, Santirbazar and Udaipur. Speakers of this dialect live in a compact dialect area. 6. Uchoi: This is the smallest dialect of Kokborok and the people speaking this dialect live in areas of the sub-divisions of Amarpur and Kanchanpur. In comparison to other dialects, the number of speakers of this dialect is less. 7. Koloi: Koloi dialect area falls under the sub-division of Teliamura, Amarpur and Longtarai valley. They originally belong to Halam community. 8. Rupini: This dialect is spoken in areas of Jirania Block of the Sadar subdivision, and in areas of Teliamura, Dharmanagar, Kumarghat and Longtarai valley sub-divisions.

Sub-Dialects: There are different opinions regarding the number of sub- dialects of the above-mentioned eight (8) dialects of Kokborok. The sub- dialects may be more familiar as clan and number of clans of each dialect have a distinct identity. Some are based on the name of a famous person and some are on skillfulness of the particular group of people like the handicraft, weaving, sweet tune, and good speakers etc. The number of sub-dialects (Binary Debbarma, 2009) of each dialect of Kokborok is as: (1). Debbarma → 11 sub-dialects, (2). Reang →17 sub-dialects, (3). Jamatia →03 sub-dialects, (4). Noatia → 21 sub-dialects, (5). Murasing →09 sub-dialects, (6). Uchoi →

Chapter 1: Introduction

06 sub-dialects, (7). Koloi → 08 sub-dialects and (8). Rupini → 11 sub- dialects.

1.4 Kokborok: A brief historical note Ethnically the Borok or Tripuri community is the part of Boro people of Assam state of North-East India. Kokborok is the mother tongue of the Borok or Tripuri community. Even though they were part of Boro people of Assam, they were recognized as unique ethnic group by the then British government. Kokborok is one of the oldest languages in India. Even though it is one of the oldest, the language did not vanish from the scene. However due to the social and political chaos in the state, the progress of Kokborok was hampered. There was a time when there was no one particular name for this language. For example, at one period it used to be called ‘Tipperah’ (Mr. C.W. Bolton (1876-77). In another period it used to be called ‘Tipura’ (G.A. Grierson 1903) or Tipra or ‘Mrung (S.K. Chatterji 1926) or ‘Tripura Bhasha’ (Thakur S.C. Debbarma 1931). Yet in another period it used to be called ‘Kagbarak’ (Dr. Suhas Chattopadhyay 1972). According to K.K. Choudhury and R.K. Acharyya (2007), it is Thakkur Radha Mohan Debbarma who for the first time used the term ‘Kokborok’ to designate the language of eight hill tribes of Tripura as ‘Kokborok’ and this was in 1900. Further, it is Radha Mohan who finally and permanently fixed the name ‘Kokborok’ for this language with its present spelling. Since then this language is popularly known as ‘Kokborok’ among the Borok or Tripuri community.

1.5 Kokborok speakers and its linguistic boundaries Kokborok speaking people are found mainly in Tripura and in the Chittagong Hill Tracts (Bangladesh). The circle in the following Map indicates the existing linguistic boundaries of Kokborok.

Chapter 1: Introduction

Map : The existing linguistic boundaries of the Kokborok.

Speakers of this language are also found in some of the North-Eastern State of India such as Mizoram, Assam, Meghalaya and Manipur. Further they are traced in Myanmar and Nepal as well. According to1991 census, there are 649, 940 Kokborok speakers who are spread all over India. In Tripura, where Kokborok is main language, 647, 847 Kokborok speakers are recorded (census 1991), which is 93.22% of the total tribal population and 23.50% of the state’s total population. It may be noted that the highest number of Kokborok speakers is noticed in west Tripura (300, 484) followed by South Tripura (220, 770) and followed by North Tripura (126, 593) (census, 1991). It may also be mentioned that Kokborok speaking people are living in different districts of neighbouring Bangladesh,

Chapter 1: Introduction constituting more than five lakh people. Further, more than one lakh Bengali speakers of the state (Tripura) speak Kokborok with their Kokborok speaking neighbours. According to one estimate (e.g. K.K. Choudhury 2007; Binoy Debbarma 2003), the actual number of Kokborok speakers including Bengali is more than 15 lakh. This data is also available in “Kokborok Obhidhan O Vyakaran” (Kokborok dictionary and grammar) written by Surendralal Tripura of Bangladesh. This book has been published by Tribal cultural Institute, Rangamati, Bangladesh.

1.6 Genetic classification of Kokborok and its place among Modern Tibeto-Burman languages During the last one hundred years or so, various linguists have attempted to classify the Tibet-Burman languages (e.g. Grierson 1903/reprint 1967, Anthony Arlotto, 1972; Scott Delancey, 1987; AnvitaAbbi, 2001). However, these linguists do not always agree with one another with respect to classification of these languages. In some cases, there still exists a good deal of controversy. To begin with, one of the earliest classifications of the Tibeto-Burman languages is by Grierson (1903) where he placed Tipura (now Kokborok) in Tibeto-Burman family as shown in the following: 1. True Bara (Kachari and Mech ) 2. Rabha 3. Lalung 4. Dimasa (or Hills Kachari) 5. Garo (or Mande) 6. Tipura (now Kokborok) 7. Chutiya

One of the latest classifications of modern Tibeto-Burman languages is that of Scott Delancey as shown in figure 1.6 (a) . After his long research,

Chapter 1: Introduction

Scott Delancey (from the University of Oregon) wrote a paper on Sino- Tibetan languages and it was edited by Bernard Comrie and published in the book viz “The World’s Major Languages” in 1987. In his paper, Scott Delancey gives a clear schema of the Modern Tibeto-Burman language family. He says, in East Asia the most important language family is the Sino- Tibetan. This language family has two main branches (1) the Tibeto-Burman and (2) the Sinitic. To the former branch belong two most important languages viz Tibetan and Burmese. The Sinitic group includes most of the Chinese languages.

Figure 1.6 (a): The schematic representation of Scott Delancey’s “The Modern Tibeto- Burman language family”.

It is an established fact that Kokborok, the language of the Borok race, belongs to the large Tibeto-Burman language family. This language family can be grouped into several sub-families and the Bodo-Garo is one of

Chapter 1: Introduction them. Linguistic analysis shows that a good number of languages spoken mainly in North Eastern India belongs to this Bodo-Garo sub-family and Kokborok along with its dialects is one of them. K.K.Choudhury (2007) opines that the Kokborok has eight (8) dialects, viz (1) Reang (2) Debbarma (3) Jamatia (4) Noatia (5) Murasing (6) Uchoi (7) Koloi and (8) Rupini. Needless to say that all these are genetically related dialects. As it is widely known, Kokborok and its sister languages such as Bodo, Garo, Dimasa, Mech, Hojai, Rabha, Lalung, Chutia etc. belong to the Bodo-Garo sub-family as shown in figure 1.6 (b) . The Bodo-Garo sub-family in turn can be linked with the Tibeto-Burman language family that is given by Scott Delancy. This is shown in figure 1.6 (c) .

Figure: 1.6 (b): Bodo-Garo Language group.

Chapter 1: Introduction

Figure: 1.6 (c): Position of Kokborok among the modern Tibeto-Burman languages.

1.7 Kokborok: Script and Orthography Kokborok had a script called ‘Koloma’. In 12 th century, the Chronicle of the Borok or Tripura Kings was written in the form of a book called ‘Rajratnakar’. This book was originally written in Kokborok using Koloma script by Durlabendra Chontai. In course of time, Sukreswar and Vaneswar translated it into Sanskrit. Later on, the ‘Rajratnakar’ was again

Chapter 1: Introduction translated into Bengali in blank verse by Kailash Chandra Singha. Due to this kind of translation and retranslation in due course of time, the Koloma script vanished completely and in the process ‘Rajratnakar’ was also lost. In view of the above, it may safely be assumed that Kokborok developed much earlier, that is, may be seven (7) hundred years ago. However, in due course of time the kings of Borok or Tripuri nation ignored their own mother tongue and culture. Thus for example, in 19 th century, the then King Birchandra (1862-96) introduced Bengali as the royal language. The successors of Birchandra also put their efforts to abolish Kokborok and Borok culture. This may be the reason why at one time Kokborok was in pathetic condition. The present Borok or Tripuri educated people started searching for a suitable script with scientific basis to write Kokborok. They found Roman as the most suitable and scientific script for their mother tongue. Therefore 90% of the Borok people have now started writing Kokborok in Roman Script. However, a very negligible percentage of people are using Bengali Script for Kokborok. It may be noted that all the English alphabetical letters are not needed to write Kokborok. For representing the sounds of Kokborok, only twenty Roman letters are sufficient. On the basis of Kokborok phonological system only the following letters have been retained: { A, B, C, D, E, G, H, I, J, K, L, M, N, O, P, R, S, T, U, Y }.

1.8 The present Status of Kokborok Kokborok now is a distinct language and is recognized by the Tripura government as a state language along with Bengali. The Tripura Legislative Assembly by way of enacting a law has recognized it as state language in 1963. In a related development in 1975-76, the Tripura Government declared Kokborok as a medium of instruction for Kokborok speaking students.

Chapter 1: Introduction

Initially it was introduced at primary level and now it has been introduced at secondary level too. On 19 th January 1979, the left front Government recognized Kokborok as one of the official languages through an enactment of a bill in Tripura legislative assembly. In order to popularize the language, a certificate course of Kokborok was launched in Tripura University in 1993. Currently the University is running one year Diploma and Advance Diploma courses in Kokborok language and literature. Kokborok has also been introduced as a subject in foundation course at college level. However, for writing purpose, Debbarma or Puran Tripuri which is one of the eight (8) major dialects has been selected as standard. A number of publishers viz Kokborok Tei Hukumu Mission, Kokborok Sahitya Samsad etc. are publishing books in Kokborok every year. The creative writers are writing poetry, stories, novels etc. Side by side, they also pay attention to translate the Indian as well as the foreign literature into Kokborok. Kokborok now is widely used in both Print media and mass media. The government brings out a weekly newspaper viz “Tripura Kagtoon” in which two pages are devoted for literature. So many senior as well as young poets and writers come forward to contribute in ‘Tripura Kagtoon’. The Agartala Centre of All India Radio broadcasts Kokborok programmes, which include news item, songs, poetry, speech, conversation etc. The Agartala centre of Doordarshan provides some space for the telecast of Kokborok news, folk songs, modern songs, dance programmers etc. The progress is seen in the field of music and drama. However, the development is slow in the arena of cinema. Thus, Kokborok is occupying a high status not only in the field of language and literature but in the tradition and culture too. It can be said that efforts for an all-round development of this language are going on. These efforts will definitely bear fruit in the days to come.

Chapter 1: Introduction

1.9 Literature Review Kokborok is clearly a member of Bodo-Garo sub-family of Tibeto- Burman languages, which includes Bodo (Boro), Garo, Dimas etc. Development of Kokborok has been loosely related with Bodo language. Yet there is a great paucity of early written materials in Kokborok, and it would indeed be true to say that the reconstruction of Kokborok linguistic history needs a great deal of speculation. In this section, an attempt is made to present a brief survey of linguistic and phonetic studies done on Kokborok both in Tripura and outside Tripura.

1.9.1 Studies done on Kokborok While searching for reference materials for the present study this researcher tried to seek books, journals, articles, etc and he could lay his hands on some of these. These materials show that there has been little work on the Kokborok phonetics, though, much work is available on phonetics of other languages. No work on Kokborok acoustic phonetics is found either in Tripura or outside Tripura. Lack of technical facilities, lack of trained researchers, lack of interest on the part of scholars and above all relatively undeveloped state of Kokborok linguistics are some of the reasons for the absence of acoustic study on this language. The present study may be termed as the first major study on Kokborok acoustic phonetics. It must be mentioned that dearth of proper materials on phonetics or acoustic phonetics in relation to Kokborok made the present researcher’s journey a bit difficult. However, some works that are available on Kokborok helped him as guidelines for his acoustic analysis in the present study. Of the works that were done and presently available the first one is that of Kazi Daulat Ahmed’s ‘ Kok-Boroma’ . This work was in fact in Bengali script. It appeared in 1897. Primarily it is Kokborok grammar for basic

Chapter 1: Introduction learning. It must be mentioned that Kazi’s book is the first book which has listed the Kokborok phonemes. Another earliest publication, which describes the sounds of Kokborok is Thakur Radha Mohan Debbarma’s (1900) ‘Kokborokma ’ (a grammar) and a Dictionary. Radha Mohan in fact was a noble of Maharaja Radha Kishore Manikya the then King of Tripura. It must be pointed out that work on Kokborok in real sense started with Radha Mohan’s ‘Kokborokma’. Radha Mohan was also entrusted with the responsibility of taking all the possible steps for educational growth of the hill tribes of Tripura by the then king. Radha Mohan found that eight communities among the tribal people use similar sounds and speak almost similar dialect among themselves and can understand each other. Radha Mohan in his pioneering work ‘Kokborokma’ made use of all the Bengali alphabet along with their sounds and developed the Kokborok spelling system following the orthography of Bengali. Almost at the same time G.A. Grierson compiled the ‘Linguistic Survey of India ’ which was published in 1903. It gave due regard to Kokborok. In his linguistic survey of India (3:2), Grierson named this language as ‘Tipura’ and mentioned the number of speakers and the linguistic boundaries of the language. He also gave some translated passages and a long word-list to show the phonological variation of the spelling system between Kokborok and its sister languages such as Bodo, Garo, Dimasa etc. After a long gap in 1967 Dr. Suhas Chattopadhyay, the then lecturer of comparative philology at Calcutta University undertook a research on Kokborok along with his two research scholar namely Shyamsundar Bhattacharya and Kumud Kundu Choudhury. Dr. Suhas Chatterjee reviewed the existing orthography of Kokborok and added new dimensions to the same. After five years of meticulous and painstaking research, he published his findings in a book entitled ‘Tripurar Kagbarak Bhashar Likhito rupe Uttaran ’. This book appeared in 1972. Findings of the book are as follows:

Chapter 1: Introduction

• Kokborok sound system has twenty seven phonemes, six vowel phonemes, twenty one consonant phonemes and two to four tone phonemes. • Kokborok does not have any conjunct letter. • Every fourth letter of five vargas is absent in Kokborok sound system. • There is no palatal, dental and cerebral sound in Kokborok. • Retroflex sound is conspicuous by its absence in Kokborok. • Kokborok has neither long /i/nor long /u/.

There after, we have a scholar from the Central Institute of Indian Language (CIIL), Mysore, Dr. Pushpa Karapurkar Pai. She came to Tripura to study Kokborok phonetics. After her research on Kokborok, she published her findings in two books, viz ‘Tripuri phonetic Reader ’ and ‘ Kokborok Grammar ’. These books appeared in1972 and 1976 respectively. In her books, she gave a detailed account of Kokborok phonetics and phonology. In her ‘Kokborok grammar ’, she specifically mentions that Kokborok has altogether thirty phonemes including tones out of which twenty one are consonants, seven vowels and two tones. In addition to this, she also throws some light on the morphophonemies, morphology and syntax of Kokborok in her grammar. In 1981, Santosh Kumar Chakraborty submitted his doctorial dissertation entitled ‘A study of Tipura language ’ at Bardhaman University. His study deals with phonological, morphological, syntactic and semantic aspects of Kokborok. In 2008, another dedicated scholar, Mrs. Ajita Tripura also submitted her M.Phil dissertation entitled ‘A comparative study of Kokborok, English and Bengali Language ’ at Madurai Kamraj University. Her dissertation was published in 2011. It dealt with areas concerning Kokborok syntax. To be more specific she made a comparative study of movement rules in Kokborok, English and Bengali.

Chapter 1: Introduction

In 1983, there appeared Prof. Prabhas Chandra Dhar’s grammar entitled ‘ Kokborok Swrwngma’ . In his grammar, he made an attempt to give an account of Kokborok sound system. He said that twenty eight phonemes are needed to write Kokborok. Out of these twenty eight, seven are vowels and twenty one are consonants. He also included in his grammar, Kokborok Parts of speech, Tense, Tones etc. Later on in 1987, Prof. Prabhas Chandra Dhar edited a Kokborok Bangla-English Dictionary entitled ‘ Kok-Kutumma ’. In his dictionary, he briefly described Kokborok phonology, morphology, syntax, case etc. In his brief account, he mentioned the following phonological features of Kokborok: • Length of vowels does not affect meaning in this language. • There is no voiced aspirated sound in this language. • There is no retroflex sound in this language. • The Pronunciation of the letter / ɯ/ of Kokborok may be heard like /u/by the unaccustomed ear etc.

In 2001, another ‘Concise Kokborok-English-Bengali Dictionary ’ appeared which was compiled by Binary Debbarma. In the introduction of his dictionary, he discussed Kokborok sound system very briefly. In 1988, Dr. Sudhanshu Bikash Shah’s book entitled ‘ Origin and Structure of Kokborok ’ was published. In his book, Dr. Shah has dealt with Kokborok sounds. He has also talked about some grammatical aspects of the language. Dr. Shah has also pointed out that to write Kokborok in Roman script almost all the English alphabetical letters are needed except { F, Q, V, X, Z }. It is in 2003 two papers were published by “Kokborok Tei Hukumu Mission”. Both these papers were written in Kokborok. Of these the first paper, viz ‘Kokborok is one of the Rich languages in the world ’ was authored by Mr. Binoy Debbarma and translated by Rev. Naphurai Jamatia

Chapter 1: Introduction into English. This paper was submitted to the 4 th International symposium on language and linguistics, Pan-Asiatic Linguistics held in January 1996 at Institute of Language and Culture for Rural Development, Mohidol University at Salaya, Bangkok, Thailand. This paper discusses the script issue of the language. It says ‘Koloma’ was the original script for this language but unfortunately, it was lost. It also highlighted some linguistic aspects of the language such as phonetics, phonology, morphology, syntax, semantics, tones etc. The second paper is ‘Kokborok is the language of the Borok people in Tripura, India – A brief outline ’. This paper was also written by Binoy Debbarma. It was presented in the 5 th International symposium on language and linguistics, Pan-Asiatic linguistic 2000, organized by the Vietnam National University at Ho Chi Minh City, Vietnam, in November 2000. This paper talks about the speakers and the linguistic boundaries of the Kokborok. It also gives a brief account of the present status of language. Debbarma also mentions about Twipra Era (Tripura Calendar), Borok’s religion and their customs in his paper. He gives family tree of Sino-Tibetan languages in order to locate the Kokborok in Modern Tibeto-Burman family. In addition to this, the paper includes a detailed word-list of Kokborok and its sister languages such as Bodo, Dimosa, Garo, Rabha, Lalung etc. In 2003, there appeared a detailed article by Dr. Francois Jacquesson entitled ‘Kokborok: A short Analysis ’. This article is based on Agartala Dialect of Kokborok. In this, Jacquesson threw some light on Kokborok sound system. Later on in 2008, Jacquesson’s ‘ A Kokborok Grammar ’ was published which is also based on Agartala Dialect. In this grammar, the author gives a detailed account of Kokborok Phonetics and Phonology. He also discusses some grammatical aspects of the language. In 2007, Kumud Kundu Choudhury’s book, viz ‘Kokborok-A promising Tribal language of North East India ’ was published. This piece of work

Chapter 1: Introduction presents a brief synchronic description of the language. There is also a brief mention of Kokborok phonetics, morphology, tones, etc in the book. In 2010, another book by K.K. Choudhury entitled ‘ Kokborok dhanibichar ’ appeared. This book is written in Bengali and gives a detail account of phonetic aspects of Kokborok. Dr. Rupak Debnath, a prominent writer undertook a research on Kokborok language and its origin. He reviewed the origin and development of the Kokborok language in his research. After a long period of meticulous and painstaking research, he came up with a book entitled ‘ Kokborok: Language Origin and Development ’. This book appeared in 2014. In this book, there is a special mention of the history and origin of Kokborok language and the sources of Kokborok vocabulary. In addition to this, the book also discusses the Kokborok phonology, morphology, tones, etc. Now various other scholars are also contributing a lot to the Kokborok language and linguistics. These scholars are working on different aspects of Kokborok in different universities of the country.

1.10 Theoretical Basis The theoretical issues include the review of the acoustic aspects of speech, acoustic cues, the acoustic dimensions of speech such as duration, voice onset time (VOT), fundamental frequency (f 0), formant frequency and formant transition etc.

1.10.1 The Acoustic Phonetics Acoustics is a branch of physics, which aims at describing the physical properties of speech sounds. According to Fant (1957), “The acoustic of speech include, in a broad sense, both the theory of speech as wave motion and also how speech waves are produced and heard”.

Chapter 1: Introduction

The sound waves are the product of the vocal tract filter and source. Richard Ogden (2009) defines acoustic phonetics as follows: “The sounds of speech are made by changes to air pressure that are caused by airflow through the vocal tract. As the air moves, it causes perturbations, which the ear picks up. The ear converts physical movements in the air into electrical signals that are sent to the brain, which is where processing of other kind (such as detecting meaningful units like sounds, words, sentences and so on) occurs. Technology makes it possible to convert these changes of air pressure into picture; and being static and unchanging, these pictures allows us to examine more of the detail of talk as it happened. This kind of phonetics is known as acoustic phonetics”.

1.10.2 Acoustics of Speech Production Knowledge of acoustic phonetics is derived from the interaction of phonetics with the discipline of engineering-electronics; linguistics-phonology and psychology-cognitive science, which a phonetician uses to describe the sounds and this results in acoustic phonetics. The basic theory of these terms is based on Fant (1970), Fry (1979) and O’Shaughnessy (1987) etc.

Calvert, D.R (1992) says that ‘the acoustic description of speech is the result of the various processes of respiration, phonation, resonation and articulation. The acoustic signal or the speech wave is the product of a source and a filtering process. Acoustic phonetics deals with the structure of speech as sound wave. Articulation is a continuity of movement of speech organs. The resulting continuous variations in the dimensions of the vocal cavities determine the variations of the vocal tract resonance frequencies. There is thus a continuity of the vocal tract resonance frequencies within any length of utterance and across any sound during speech production. A constriction is usually formed in the airways at the level of the vocal folds within the larynx. This constricted region, which is just a few millimeter long, is called glottis, and forms the dividing line between the sub-glottal system and the supraglottal system’.

Chapter 1: Introduction

For the production of most speech sounds, the sub-glottal system provides the energy in the air flow, and the laryngeal and supraglottal structures are responsible for the modulation of the airflow to produce audible sound.

1.10.3 Acoustic Theory of Speech Production Human beings speak by using their vocal cords as a sound source, and make rapid movements of the articulatory organs such as the tongue, lips, jaw and so on. The nasal tract begins at the velum and ends at the nostrils. When the velum is lowered, the nasal tract is acoustically coupled to the vocal tract to produce the nasal sounds of speech. Sound quality is dependent on the length, size and shape of the vocal tract. The different sounds such as vowels and consonants are produced by changes in the shape of the vocal tract. Acoustic theory involves estimation of the motion of the articulatory organs directly from speech waves and this estimation needs to be done in interactive multimedia applications to provide meaningful feedback to the listener. When different sounds are produced by varying the shape of the vocal tract, the spectral properties of the speech signal vary with time as the vocal tract shapes vary.

Speech is often talked about in terms of the source-filter theory which describes speech production as a two-stage process (i.e., vocal folds and vocal tract) involving the generation of sound source, with its own spectral shape, which is then shaped or filtered by the resonant properties of the vocal tract.

In speech, the source of sound is provided primarily by the vocal cords. Vocal cords vibration has a fundamental frequency and harmonics. The pitch of a voice is correlated to the fundamental frequency. Most of the filtering of a source spectrum is carried out by that part of the vocal tract which is anterior to the sound source. In case of a glottal 21

Chapter 1: Introduction source, the filter is the entire supra-glottal vocal tract. The vocal tract filter always includes some part of the oral cavity and can also, optionally, include the nasal cavity depending upon whether the velum is open or closed. Sound sources can be periodic/voiced or aperiodic/voiceless. Glottal sound sources can be periodic/aperiodic, whisper and /h/or mixed e.g., breathy voice. Supra-glottal sound sources that are used contrastively in speech are aperiodic or a random kind of noise, although some trill sounds can resemble periodic sources to some extent.

Figure 1.10.3 Source Filter of Speech Sounds. (After – Gunnar Fant and others c. 1950-60)

Figure 1.10.3 shows the sound source which is generated at the vocal cords as a sound source with its own spectral shape, which is then shaped or filtered by the resonant properties of the vocal tract into speech sounds. Hence, it may be said that vocal source can not account to just one frequency, but may be a range of frequencies from the fundamental to all the way up to infinity, essentially in integral multiples.

1.10.4 Standing Waves and Resonance Theory Resonance is a physical property of an object. All physical objects resonate. Some have simple, uniform resonance patterns and some have complex resonance patterns. Some resonators are highly damped and some are weakly damped. To substantiate the point the following quotations are relevant: ‘Sound may be produced as a consequence of resonance patterns within an object, but sound should not be confused with resonance’. (Clark and Yallop, 1995)

Chapter 1: Introduction

‘A guitar string of a fixed mass, length and tension has a constant characteristic resonance pattern regardless of whether it is currently producing sound or not, whether it is not vibrating, or vibrating within a vacuum. Some resonators may generate sound by exciting adjacent air particles in the surrounding medium’. (Harrington and Cassidy, 1999)

As seen from a guitar string which vibrates upon being plucked, the vibrations of the strings are transverse vibrations and are therefore not sound vibrations with characteristic resonant frequencies determined by the physical properties of the string. The guitar string collides with the surrounding air and generates longitudinal pressure sound waves in that medium. The sounds waves in the air have frequency patterns related to the frequency patterns of the vibrating string and thus of the string’s resonance characteristics, but, the sound waveform of the resulting sound bears little obvious visual resemblance to the vibratory pattern of the string that generated it. Resonances are vibratory characteristics of a resonating body. In the case of an air filled tube the resonance characteristics exist even when there is no sound being produced. When a vowel sound is produced, the resonances of the vocal tract selectively enhance sound vibrations close to the resonance frequencies and selectively attenuate sound vibrations remote from the resonance frequencies. This results in peaks in the acoustic spectrum of the resulting speech sound. These acoustic spectral peaks are called formants, particularly when they occur in vowels and vowel-like consonants.

1.10.5 Sound Sources in the Vocal Tract There are three kinds of speech source: periodic/voicing or vibration of the vocal folds, aperiodic noise/voiceless and, as some phoneticians consider, non-voicing/silence as well. Periodic vibration of the vocal folds is known as phonation. Phonation provides the periodic sound source for all voiced speech sounds. Changes in the settings of the muscles of the larynx can affect the rate of phonation, the 23

Chapter 1: Introduction

fundamental frequency (f 0) as well as the mode of vibration. Modes of vibration include modal phonation as well as breathy voice, creaky voice, falsetto voice, and certain pathological modes of vibration. The voiced source produced at the glottis also is mixed with this modulated noise source. High frequency components of the phonation source are attenuated by passage of the sound through the constriction, but lower frequency components do make their way into the anterior chamber where they mix with the modulated noise source. Further, audible low frequency components of the voiced source can also pass through the tissues of the vocal tract.

1.10.6 Vocal Tract Resonance / Tube Models The vocal tract can be treated mathematically as a single uniform tube closed at one end – the glottis; and open at the other – the lips, for the purposes of calculating the resonance of the vocal tract. These resonances of

the vocal tract can be calculated by the formula → [ F = ]. For all speech sounds, the configuration of the vocal tract is much more complex. The actual cross-sectional shape of the vocal tract varies greatly along its length, even during the production of a neutral vowel. But these variations in shape have an almost negligible effect on resonance. To substantiate the point the following quotations are relevant: ‘Cross-sectional area at each point is, on the other hand, the main predictor of vocal tract resonance. Most mathematical models of vocal tract resonance assume a circular cross-section shape with a cross- sectional area equivalent to that of the vocal tract at each measured point between the lips and glottis. The four-tube, three-parameter model provides a sufficiently accurate prediction of most vowel sounds, and tube models can also be used to predict consonant resonance patterns. The simple three- parameter model can provide a reasonable prediction of the resonance patterns of the consonants, consonants with a tongue constriction. The acoustic theory makes use of an idealized model of the vocal tract in order to predict how different vocal tract shapes and action contribute to the acoustic signal’. (Fant, 1960)

Chapter 1: Introduction

‘Formants can accurately be predicted by reducing the complexities of the vocal tract to the three-parameter, four-tube model’. (Fant, 1960)

‘The Acoustic theory leads to the prediction that the source signal can be modelled as independent from the filter characteristics of the vocal tract, an idea that is fundamental to acoustic phonetics, to formant- based speech synthesis, and to linear predictive coding (LPC) which allows formants to be cracked digitally. The idea is that the relationship between speech production and acoustic is non-linear, as predicted by the quantal theory of speech production. Such discontinuities are exploited by languages in building up their sound systems founded upon models that relate idealized vocal tract to the acoustic signal’. (Kenneth N. Stevens, 1989)

‘Various sounds are formed by varying the shape of the vocal tract and hence, the spectral properties of the speech signal vary with time as the vocal tract shape varies. Phonology assumes a system of contrast where phonemes differ in terms of features chosen from a universally defined feature set such as, duration, spectral properties and its relative amplitude’. (Lahiri and Reetz, 2002)

1.10.7 Perturbation Theory of Speech Production The vocal tract during the production of vowels and vowel-like consonants can be described as a tube open at one end, the lips, and closed at the other, the glottis. As Ladefoged and Johnson pointed out that:

‘The vocal tract as a tube with a uniform diameter has simultaneous resonance frequencies. These resonance frequencies change in predictable ways when the tube is squeezed at various locations. This means that we can model the acoustics of vowels in terms of perturbations of the uniform tube. When the lips are rounded, the diameter of the vocal tract is smaller at the lips than at other locations in the vocal tract. With perturbation theory, we know the acoustic effect of constriction at the lips, so we can predict the formant frequency differences between rounded and unrounded vowels. For each formant, there are locations in the vocal tract where constriction will cause the formant frequency to rise, and locations where constriction will cause the frequency to fall.

Chapter 1: Introduction

Figure 1.10.7 The locations for f 1, f 2, and f 3 in the vocal tract. (After - Ladefoged and Johnson, 2001)

Figure 1.10.7 shows these locations for f 1, f 2, and f 3. In this figure, the vocal tract is pictured three times, once for each formant, and is represented as a tube that has the same diameter for its whole length and is closed at the glottis and open at the lips. The fact that three resonant waves can be present in the vocal tract at the same time is difficult to appreciate but true. The perturbation theory says that if there is a constriction at a velocity maximum (V) in a resonant wave then, the frequency of that resonance will decrease, and if there is a constriction at a point of maximum pressure (P), then the frequency of the resonance will increase’. (Ladefoged and Johnson, 2001)

1.11 The Acoustic Dimension of Speech Sounds There are two main differences between vowels and consonants acoustically. Vowels are highly resonant as they are always produced with the vocal tract open and hence are always voiced and they are periodic. Consonants are produced with a constriction of the vocal cords at one place or the other so they have a weaker resonance. They can be produced as periodic/voiced, aperiodic/voiceless or at times a combination of sound sources.

1.12 Duration of Speech Sounds Length or duration is an important aspect in assessing the acoustic analysis of the sound segments. “Duration is type of modification of articulation” (Fant, 1968; Catford, 1977). A sound can be long or short depending upon the articulatory posture of the vocal tract. “The physiological

Chapter 1: Introduction mechanism that is ultimately responsible for quantity phenomena is the process involved in the timing of articulatory movements” (Lehiste, 1970). The distinction in sound duration may be made by taking into account several factors (Lehiste, 1970). Some factors that contribute to variations in duration are: nature of the segments, place of articulation, manner of articulation, preceding and following vowel or consonant context. In fact duration is one of the few acoustic parameters which can precisely be measured. Duration is the spatial distance from a point in time where regularly appearing sound waves as well as vertical striations of spectrogram are observed for a consonant, to the point in time where formant energy ends in association with the oral conclusion of the terminal sound (vowel/consonant). Voicing quality of sound segment is also another factor that contributes to the variations in duration measurements. Ladefoged (2002) stated that ‘voiceless consonants are longer than voiced consonants’. The acoustic measurement of consonant phonemes depends mostly on the manner, place of articulation and voicing quality. Duration is varied on the position it appears in a monosyllabic word, polysyllabic word and connected speech as well. Hardcastle (1973) stated that ‘the faster the movement of the articulator is, the shorter the closure duration’. Maddieson (1991) stated that. ‘closure duration of a stop reduces with the backness of the tongue’. Duration also is varied among the different speakers irrespective of gender and age.

1.12.1 Voice Onset Time (VOT) Voice Onset Time (usually abbreviated as VOT) is the duration or time duration between the release of a stop and the starting of a following vowel. Ladefoged and Johnson (2001) define VOT as follows:

‘Voice Onset Time (VOT) is the interval between the release of a closure and the start of the voicing’.

Chapter 1: Introduction

Similarly, Lisker and Abramson (1964); Keating (1984); Klatt (1975) give the following definition: ‘VOT is the interval between the release of a plosive and the onset of vocal cords vibration and is measured from acoustic display as the time between the release burst and the first quasi periodicity in the acoustic signal’.

Figure 1.12.1 : Waveform and spectrogram shows VOT in the words /apa/ (father) and /ap ha/ (my father).

VOT can be of three different types. Zero VOT is the first type in which the onset of vocal folds vibration approximately coincides with the stop release. The second one is positive VOT where there is a delay in the onset of vocal folds vibration after the stop release (also called lag VOT). This type is further divided into two namely short lag and long lag VOT. The third type is negative VOT, also known as lead VOT, in which the onset of vocal cords vibration precedes the plosive release. Fischer-Jørgensen (1954), Peterson and Lehiste (1960) stated that ‘further the back the place of articulation is the longer the VOT’. Hardcastle (1973) stated that ‘the faster the movement of the articulator is, the shorter the VOT’. Lehiste (1960) stated that ‘characteristically VOT increase with the

Chapter 1: Introduction backness of the stop’s place of articulation’. Maddieson (1997) stated that ‘the stop closure duration for bilabial stops is longer than that of alveolar and velar, possibly due to different degree of air pressure in the cavity behind the constriction’.

1.13 Fundamental frequency (f 0) of Speech Sounds The number of complete cycles the vocal folds make in one second is called the fundamental frequency. It is often symbolized as f 0 and is perceived by listener as pitch. It is measured in Hertz (Hz). A speech signal has many acoustic features from which measurements can be taken. Beginning as a vibration at the vocal folds, the speech signals have a pitch or fundamental frequency , which is determined mainly by the physical dimensions such as the mass, length and dimension of the speaker’s vocal folds. The same utterance can vary to a large extent depending on the way it is pronounced by different speakers. The pitch track is often called a pitch contour. It has a common usage by different phoneticians. The measurement of fundamental frequency (f 0) is done on the basis of pitch contour.

The range of fundamental frequency (f 0) for individual speaker depends mainly on the shape and size of the vocal folds. Because of the shape and size, there are differences of fundamental frequency (f 0) amongst the male, female and children in their speech. Men’s vocal folds size is greater in length than women and children. But the women’s vocal folds size is greater in length than children’ (Lawrence, Gloria and Katherine; 2007). K.Wu and Childers (1991) observed that a fundamental difference between male and female speaker’s f 0 is bound to be there in their speech. Ledefoged and Johnson (2001) stated that ‘the highest pitch is associated with /t/, the next with /k/, and the lowest with /p/’.

Chapter 1: Introduction

Furthermore, as the length of the vocal folds is proportional to the length of the vocal tract, f 0 and the positions of the formant frequencies are also proportional: long vocal folds, typical for males, generally imply low frequencies.

1.14 Formant Frequency of Speech Sounds Formant Frequency or frequency is the rate of oscillation in air pressure in a periodic sound wave. The formant frequencies of the vocal tract are leveled as f 1, f 2, f 3 and so on. The shape and length of the vocal tract, determine the location of the formant frequencies f1, f 2, f 3. ‘The formant frequencies, of course, depend upon the shape and dimensions of the vocal tract, each shape being characterized by a set of formant frequencies’ (Fant, 1960). The sound when produced is the sum of different vibrations and has corresponding frequency components in its spectrum. The black and slightly dark regions in the spectra correspond to the basic frequencies of the vibrations of the air in the vocal tract. The regions of the spectrum in which the frequency components are relatively large are known as formants (every region of vowel seen to be large, so is treated as formants). The formant shapes and their concentration of energy does not only help the recognition of sounds but also gives us a detailed image of how each sound behaves differently from the other. The formants of a sound are thus aspects of it which are directly dependent on the shape of the vocal tract, and are largely responsible for the characteristic quality. The formant relations that specify the sounds of Kokborok are inherently related rather than absolute. The vowels are produced with free airflow and spontaneous vibration of vocal folds and the consonants are produced with obstruction in the vocal tract. However, Fujimura (1962) determined that ‘in nasal consonants, there is a high density of formants and the existence of anti-formants. The formant

Chapter 1: Introduction frequency measurement of nasal sounds depends on the length of the oral cavity and the measurement of anti-formants of nasal sounds depends on the length of the nasal cavity’.

1.14.1 Formant Transition of Speech Sounds Transition is the linkage between adjacent sounds. According to Trask (1996), ‘Transition is any movement of the vocal organs during speech from one more-or-less steady position to another. The acoustic effect of such a movement, particularly, is revealed in the upward or downward movement of the formants in a sound spectrogram’. Catford (2003) pointed out that there are two different ways of making the transition from one consonantal articulation to another: what we call (a) close transition and (b) open transition. (a) Close transition: where there is a linkage between the sounds. (b) Open transition: where there is break in articulation.

1.15 Digitisation of Speech Wave The free availability of computer software for generating spectrograms, processing speech signals and for labeling speech data have proved very useful in the area of acoustic phonetics. The ready and easy accessible nature of the regular and free availability of computers containing integrated high- quality digital sound capabilities and the combined effort of computer programmers’ participation in developing the software for speech analysis of greater precision have made extensive use of speech analysis possible. The most popular and tested ways of analyzing speech are:

1.15.1 Spectrogram A spectrogram here refers specifically to a sound spectrogram. It is a visual representation of an acoustic signal. A Fast Fourier Transform is applied to an electronically recorded sound. When this analysis takes place, a

Chapter 1: Introduction sample wave is essentially separated. The waves get separated into constituent frequencies and their amplitude are then displayed visually, with degrees of amplitude represented from dark to light bands. Dark signifies high energy and white signifies no energy, at various frequencies which are usually represented on the vertical axis across horizontal axis which represents time. The spectrographic display of speech is a visual feedback tool, which has become increasingly popular more recently. The spectrograms provide a visual representation of the frequency, intensity, and time domains of an acoustic signal. Spectrographic displays can provide many segmental and suprasegmental speech features. Simultaneously the spectrographic displays are capable of providing visual contrast between correct model and incorrect production (Ertmer et al, 1996). A speech waveform is very complex and can be analysed as the summation of a large number of simple sinusoidal frequency components. A two-dimensional plot showing the relative amplitude of these components over some small window of time is called power spectrum. A spectrogram provides a visual three-dimensional representation of energy, indicated by darkness of shading at a range of frequencies, Y-axis as a function of time and X-axis is a temporally ordered stack of numerous power spectra viewed from a vantage point above their peaks.

1.15.2 Narrow Band Spectrogram Different levels of resolutions of spectrograms are achieved depending upon the Fourier analysis window. A longer window resolves the harmonics that is the component frequencies, but the time resolution is smeared up. So, complete information may not be retrieved about the changes that occur in the vocal tract as we speak.

Chapter 1: Introduction

1.15.3 Wide/Broad Band Spectrogram In a broad/wide band spectrogram, a short analysis window is applied. The adjacent frequencies get smeared up but time resolution is very clear. In wide band spectrograms, the striation or individual pitch periods can be seen along with the formant structure, and these spectrograms are popularly used as they give us information about the vocal tract changes. In this study broad band spectrograms are used. A wide band spectrogram displays vocal tract resonances as dark bands or formants, different vocal tract shapes produce different formant patterns. As the vocal tract changes shape, so do the formants change frequency. Frequency of any given formant depends upon the size and shape of the vocal tract.

1.16 Description of Acoustic Cues The investigation of speech data in the study observes the acoustic cues which can identify place and manner of speech sounds. Kokborok speech sounds are observed in isolation, in monosyllabic words, in polysyllabic words and also in connected speech. For the identification of speech sounds, several basic distinctions can be observed in the following spectrogram.

Chapter 1: Introduction

Figure 1.16: Waveform and spectrogram of the word /sak čha/ (selfish).

The first distinction is between sound and silence: the dark band in the spectrogram is for sound and blank space in the spectrogram is for silence. The second distinction is between voiced and voiceless: the vertical striations in the spectrogram correspond to the vibration of the vocal fold for the voiced sound and blank spaces correspond to the closure in the vocal tract for the voiceless sound. The short noise burst in the waveform and spike in the spectrogram correspond to the aspiration. The random energy concentration in the waveform and the ‘fuzzy patch’ in higher frequency region of the spectrogram correspond to the noise or friction. There are darker horizontal bands across the spectrogram, which are starting at the bottom. The first one is called first formant (f 1) and second one is called second formant (f 2) and so on. There are in fact more formants but usually only the first three are of interest.

1.17 The Scope of the Study The study is restricted to acoustic description of the segmental aspects of Kokborok. It concentrates on the Kokborok speech sounds produced by

Chapter 1: Introduction

Kokborok speaker. It describes Kokborok speech sounds within the parameter of duration, formant frequency and formant transition as well, with the help of LPC based signal process as well as spectrogram. The articulatory description is limited to the phonological level. It is restricted to the auditory impressions and observation supplemented by field notes.

1.18 The Aims of the Study The main aim of the study is to describe the Kokborok speech sounds in terms of their acoustic dimension.

1.19 The Objectives of the study The main objectives or purpose of this study is to look at acoustic aspect of Kokborok speech sounds. Other objectives are as follows: 1. To identify the Kokborok speech sounds on spectrogram that corresponds to vocal tract. 2. To describe the acoustic aspects of Kokborok speech sounds articulated by Kokborok speaker. 3. To describe acoustic characteristics of Kokborok speech sounds in terms of speaker variations. 4. To describe acoustic features of Kokborok speech sounds in terms of gender variations.

1.20 The Hypothesis of the Study The study is based on the following hypothesis: 1. There are significant variations among the speakers in terms of duration, manner and place of articulation and rate of speaking. 2. There are significant variations in the rate of speaking in terms of formant frequency and formant transition. 3. Variations in speech can be attributed to individual speaker differences.

Chapter 1: Introduction

4. Speaker variations in articulation of speech sounds can be attributed to gender. 5. Variations in articulation of individual speech sounds of Kokborok speaker can be attributed to different positions in a word as well as in connected speech.

1.21 The Informants In total forty Kokborok speakers including fifteen (15) men, fifteen (15) women and ten (10) twelve to fifteen years old children (5 boys and 5 girls) participated in this study. The informants are listed in the following Table 1.21. All of them are native speakers of Kokborok and they belong to Tripura. All of them are multilingual. Further, they have received no phonetic training and knowledge of this kind of experiments.

Table 1.21 The list of informants.

Chapter 1: Introduction

1.22 The Data

For the acoustic analysis of Kokborok speech sounds, a list of Kokborok words was prepared and recorded. The informants were made to record atleast three readings of each word on a digital audio recorder. Before recording, a brief session of instruction regarding how and what to do was held. For familiarization, each participant rehearsed the target words. The eighth (8) Kokborok vowels, four (4) diphthongs, one (1) triphthong and nineteen consonants of the language are listed in the following in Table 1.22 (a) and (b). All these sounds are recorded in isolation, in words (monosyllabic and polysyllabic) and also in connected speech.

Table 1.22 (a): The list of the Kokborok Vowels.

Chapter 1: Introduction

Table 1.22 (b): The list of the Kokborok Consonants.

1.23 The Methodology of the Research The method of research for the present study involves collection of data by audio recording of the speech, as spoken by the informants. The following research methods are used:

1. The study involves collecting the data by audio recording the speech as spoken by the informants. The speech sounds were recorded by using a digital audio recorder (Sony: ICD-UX523F/SCE ). The data was recorded

Chapter 1: Introduction

and collected on the basis of Kokborok word lists prepared by the researcher for the purpose. 2. It consists of all the Kokborok speech sounds occurring in different word positions as well as in connected speech and in different contexts as spoken by the informants. 3. The sounds are in isolation, in words and in connected speech. The details of the acoustic aspects of sounds are described following the acoustic measures of duration, formant frequencies, formant transitions etc. 4. The articulatory description is based on perception as well as interpretation of the articulatory information derived from spectrograms. 5. In the present study, both the qualitative and quantitative research methods are used together because the qualitative research method, here, develops the quantitative research method. This study involves both qualitative and quantitative research method because of the following reason: Qualitative Quantitative

There is the involvement of This study is Mechanistic and Deductive , informants / participants in because parts equal the whole. collecting and recording of data. The researcher interacted with This study is done in highly controlled the informants and observed how setting or experimental setting (outcome they articulate speech sounds. oriented). This study uses instruments. In this research, the specific variables are studied. In this study, the researcher and In this study, the researcher tests the his biases is known to hypothesis and theory with the data. participants and participants Numbers and statistics are used to measure characteristics are also known to speech sounds. the researcher. This study involves the statistical report with correlations, comparisons of means, and statistical significance of findings.

Chapter 1: Introduction

1.24 The Acoustic Analytic Techniques Acoustic analysis of every speech sample is done by using Personal Computer (PC). Speech analysis software called ‘Praat’ is used to generate waveform as well as spectrogram. For the acoustic analysis every token is recorded. The recordings of atleast three reading of each token are made with a digital audio recorder. The first part and the last part of each of the recordings are ignored but the middle part is used for analysis. Each and every recorded token is transcribed and presented in the form of broad transcription used in International Phonetics Alphabet. It is possible to analyze sounds in terms of numbers (Ladefoged and Johnson, 2001) so that we can measure the actual frequencies of the formants. The spectrograms and the waveforms are examined very carefully for the numerical analysis of Kokborok speech sounds and then the mean value of the numbers of the sounds is taken and is represented graphically.

1.25 The Parameters of Acoustic Analysis of Speech Sounds The acoustic/spectrographic analysis and description of Kokborok speech sounds are made within the measurable scales or parameters of duration, formant frequency and formant transition as well. Among the speech sounds the Kokborok vowels fall into viz: (i) Front, (ii) Central and (iii) Back and the Kokborok consonants fall into viz: (i) Labial, (ii) Coronal, (iii) Dorso- palatal (iv) Dorso-velar and (v) Glottal. The formant frequencies are measured in Hertz keeping in mind the place and manner of articulation of each sound. The duration of each sound is measured in millisecond. Duration measurement mostly depends on manner and place of articulation and also on the position it appears in isolation, in words as well as in connected speech.

Chapter 1: Introduction

1.26 Thesis outline The thesis is structured into chapters and sections. The introduction is the first chapter. The chapter discusses the methodology, objectives and hypotheses of the research. The second chapter contains the phonological sketch of the Kokborok language. It provides the classification, description, distribution and contrast between the phonemes. It also gives spectrographic sketches of all the Kokborok phonemes and describes them on the basis of their acoustic cues. The third and fourth chapter deal with the acoustic analysis of the Kokborok phonemes. The acoustic analysis of the Kokborok phonemes is done within the parameters of duration, formant frequency and formant transition. These chapters also deal with the individual as well as gender variations of duration and formant frequency. Chapter fifth presents the conclusions and gives suggestions for future research.

**********

Chapter 2 : Phonological Sketch of the Kokborok Language ______

2.0 Overview The present chapter presents a phonological sketch of the Kokborok language. It also provides the spectrographic sketch of the Kokborok speech sounds along with their phonological analyses. The chapter is divided into two parts. Part one deals with Kokborok vowels and part two deals with Kokborok consonants. Both part one and part two give a phonemic inventory of vowels and consonants of Kokborok. Both the parts discuss classification, description and distribution of vowels as well as consonants.

Part-I: Vowels

2.1.1 Introduction Vowels can be defined in terms of both phonetics and phonology. Phonetically they are the sounds articulated with no complete closure in the mouth or a degree of narrowing which would produce audible friction; the air escapes evenly over the center of the tongue. If air escapes solely through the mouth, the vowels are said to be oral; if some air is simultaneously released through the nose, the vowels are nasalized (Crystal, 2003). From a phonological point of view, vowels are those segments which form the nucleus of syllables (Trask, 1996).

According to the articulatory setting or voice quality setting, vowels can be described and classified in terms of the following main factors:

45 Chapter 2: Phonological Sketch of the Kokborok Language

(1) The vowel height which is proportional to the first formant frequency corresponds to the vertical tongue position or the tongue height (i.e. for high and low vowels). (2) The vowel frontness and backness which is proportional to the difference between second and first formant frequencies correspond to the horizontal tongue position or the tongue frontness and backness (i.e. for front and back vowels). (3) The degree of lip rounding corresponds to the lip position which usually lowers both the second and third formant frequencies (i.e. for rounded and unrounded vowels). (4) Velic closure corresponds to the closing of either oral or nasal cavity by the velum (i.e. for oral and nasal vowels).

In establishing the vowel system of a language, several further dimensions of classification may be used. One criterion is in terms of duration (long-short) of the vowel. Another is whether, during an articulation, there is any detectable change in quality. If the quality of a vowel stays unchanged, the term pure vowel or Monophthong, is used, e.g. the pronunciation of Kokborok words /mil/ ‘plain’ /le ŋ/ ‘tired’ /tan/ ‘crisis’ etc. If there is an evident change in quality, one talks of a gliding vowel. If two auditory elements are involved, the vowel glide is referred as ‘Diphthong’, e.g. /laite/ ‘easy’ /p hai/ ‘to come’ /n ɔtɔi/ ‘aunt’ etc; if three elements are involved, the vowel glide is referred to as a ‘Triphthong’. e.g. /kuai/ ‘betel-nut’ and /nuai/ ‘brother-in-law’ etc.

2.1.2 Phonemic Inventory of the Kokborok vowels For the convenience of phonemic inventory, the sufficient data has been recorded and transcribed phonetically. Based on the data, the following

Chapter 2: Phonological Sketch of the Kokborok Language table is prepared. This table listed the vowel phonemes, diphthongs and triphthong which are found in the Kokborok language.

The Kokborok Vowels:

Table 2.1.2 The Kokborok vowel phonemes.

The Table 2.1.2 shows that Kokborok has eight (8) phonetically distinctive vowel phonemes – i.e. {/i , e , a , ə , ɯ , ɔ, o , u /}; four (4) phonologically distinctive diphthongs – i.e. {/ai/, / ɔi/, /au/, /ua/} and a triphthong – i.e. {/uai/}. This section presents the description, classification, phonemic analysis and spectrographic sketch of these vowels.

The above Table 2.1.2 is exhibiting all the Kokborok vowels in two different parameters such as (i) vowel frontness and backness and (ii) vowel height. The first parameter classifies the Kokborok vowels into (a) front (b) central and (c) back and the second parameter classifies the Kokborok vowels into (a) high (b) mid and (c) low.

According to the first parametric classification, the Kokborok vowels are: • Front vowels : Kokborok has two front vowels - /i/ and /e/ . • The central vowels : Kokborok has two central vowels - /a/ and /ə/. • The back vowels : Kokborok has four back vowels: three rounded vowels - /ɔ/, /o/ and /u/ and an unrounded vowel - /ɯ/.

Chapter 2: Phonological Sketch of the Kokborok Language

And, according to the second parametric classification, the Kokborok vowels are: • The high vowels : Kokborok has three high vowels - /i/ , /ɯ/ and /u/ . • The mid vowels : Kokborok has four mid vowels - /e/ , /ə/, /ɔ/ and /o/ . • The low vowels : Kokborok has one low vowel - /a/ .

2.1.3 Description, classification and phonemic Analysis of the Kokborok vowels The Roman script in which this language is now written does not provide separate symbols for long and short vowels. At the phonological level, Kokborok does not have instances of long and short vowels phonemes. The length of vowels does not affect meaning in this language. Further nasalized vowels too are not there in the language. In the following, we shall describe the Kokborok vowels and also present their phonemic analysis according to the two parametric classifications.

2.1.4 The first parametric classification of the Kokborok vowels Kokborok has three degrees of vowel frontness and backness, which may be termed as front, central, and back.

2.1.4.1 The front vowels in Kokborok Kokborok has two front vowels –i.e. /i/ and /e/ :

/i/

The Table 2.1.2 exhibits that Kokborok /i / is a high front unrounded vowel. The articulation of this vowel involves the front of the tongue being raised towards the hard palate giving it the effect of being high; the lips are in a spread position making it an unrounded vowel. It occurs in all word positions such as initial, medial and final. For example:

Chapter 2 : Phonological Sketch of the Kokborok Language ______

Part-I: Vowels

According to the articulatory setting or voice quality setting, vowels can be described and classified in terms of the following main factors:

45 Chapter 2: Phonological Sketch of the Kokborok Language

2.1.2 Phonemic Inventory of the Kokborok vowels For the convenience of phonemic inventory, the sufficient data has been recorded and transcribed phonetically. Based on the data, the following

Chapter 2: Phonological Sketch of the Kokborok Language table is prepared. This table listed the vowel phonemes, diphthongs and triphthong which are found in the Kokborok language.

The Kokborok Vowels:

Table 2.1.2 The Kokborok vowel phonemes.

Chapter 2: Phonological Sketch of the Kokborok Language

2.1.4 The first parametric classification of the Kokborok vowels Kokborok has three degrees of vowel frontness and backness, which may be termed as front, central, and back.

2.1.4.1 The front vowels in Kokborok Kokborok has two front vowels –i.e. /i/ and /e/ :

/i/

Chapter 2: Phonological Sketch of the Kokborok Language

Initial Medial Final Word Gloss Word Gloss Word Gloss /ib ɔ/ that /him/ to walk /čhi/ ten /im əŋ/ a dream /ri ŋ/ to call /b ɔli/ to grow /i ɡala/ this side /p hir ɔk/ to return /masi/ this world /ijar/ friend /ɡilap/ a book cover /ǰuɡali/ helper Table. 2.1.4.1 (a) : Examples of the occurrence of phoneme /i/ .

/e/

The Table 2.1.2 exhibits that Kokborok /e / is a mid front unrounded vowel. The articulation of this vowel involves the sides of tongue being raised to the sides of the palate with a smaller constriction than that created for the production of /i/. The lips are in a spread position making it an unrounded vowel. It occurs in all word positions, initial, medial and final. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /ek/ stir /bera/ to keep /ǰe/ who, which /elem/ intelligent /ǰep/ pocket /mare/ girl friend /ema ŋ/ a dream /ere ŋ/ meaningless /lete/ more

Table. 2.1.4.1 (b) : Examples of the occurrence of phoneme /e/ .

2.1.4.2 The central vowels in Kokborok Kokborok has two central vowels –i.e. / a/ and /ə / :

/a/

The Table 2.1.2 exhibits that Kokborok /a / is a low central neutral vowel. During its production the lips are neither spread nor rounded, and the tongue position is neither fronted nor backed. It occurs in all the three positions and shows a very high frequency of occurrence. For example:

Chapter 2: Phonological Sketch of the Kokborok Language

Initial Medial Final Word Gloss Word Gloss Word Gloss /a čhuk/ to sit /čhak/ red /dila/ slow man /ami ŋ/ a cat /da ŋ/ stick /ǰɔ ra/ time /ad ɔŋ / representative /ɡap/ colour /bi ɡra/ poor man

Table. 2.1.4.2 (a) : Examples of the occurrence of phoneme /a/ .

/ə/

The Table 2.1.2 shows that Kokborok /ə/ is a mid central neutral vowel. This vowel is produced with the tongue and lips in their rest positions. It occurs in word medial position only. Kokborok / ə/ shows a very less frequency of occurrence. For example: Initial Medial Final Word Gloss /s əh/ one /k ərak/ hard No occurrence /ra ŋbəta ŋ/ necklace No occurrence /k əč həra ŋ/ active /m əmla/ love affair

Table. 2.1.4.2 (b) : Examples of the occurrence of phoneme /ə/.

2.1.4.3 The Back vowels in Kokborok Kokborok has four back vowels: three rounded vowels - /ɔ/, /o/ and /u/ and an unrounded vowel - /ɯ/:

/ɯ/

The Table 2.1.2 displays that Kokborok / ɯ/ is a high back unrounded vowel. During the production of this vowel, the lips are not rounded and forward flanged, but they remain spread as they do in the case of /i/. It occurs in all the three positions but the frequency of occurrence in word medial position of this vowel is high in comparison to the initial and final positions. For example:

Chapter 2: Phonological Sketch of the Kokborok Language

Initial Medial Final Word Gloss Word Gloss Word Gloss /t hɯk/ louse /ɯŋ / to be /k ɯkr ɯk/ clean /k ɯčɯŋ / bright /ɯŋ lam/ scope / aim /r ɯ/ to give /s ɯk/ to tight /ɯŋ tɔŋ / the present /m ɯlɯk/ hiccup

Table. 2.1.4.3 (a): Examples of the occurrence of phoneme /ɯ/.

/ɔ/

The Table 2.1.2 exhibits that Kokborok / ɔ/ is mid low back rounded vowel. During its production the back part of the tongue is slightly raised, below the position for / o/ vowel. The lips are in a round position making it a rounded vowel. It occurs in all word positions: initial, medial and final. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /ɔǰɔ m/ digest /ak ɔr/ district /ɔrɔ/ here /ɔč hai/ priest /l ɔɡ e/ herewith /ɔmɔrɔ/ always /ɔsam/ crowed /b ɔrɔk/ man /ur ɔ/ there

Table. 2.1.4.3 (b): Examples of the occurrence of phoneme /ɔ/.

/o/

The Table 2.1.2 shows that Kokborok / o/ is mid high back rounded vowel. During its articulation the back of the tongue is closer to the soft palate but approximate enough for the escape of the pulmonic air. The lips are in a rounded position to make the vowel rounded. It occurs only in medial and final positions and shows very less frequency in occurrence. For example: Initial Medial Final Word Gloss Word Gloss No occurrence /jok/ pungent /r ɔmo/ pestle /ijor/ poke /ǰɔ to/ all

Table. 2.1.4.3 (c): Examples of the occurrence of phoneme /o/ .

Chapter 2: Phonological Sketch of the Kokborok Language

/u/

The Table 2.1.2 exhibits that Kokborok / u/ is high back rounded vowel. During its articulation the tongue is considerably retracted towards the soft palate and it is in a humped position but approximate enough for the escape of the pulmonic air. The lips are in a rounded position. It occurs in all the three positions; initial, medial, final. For example:

Initial Medial Final Word Gloss Word Gloss Word Gloss /ubi/ pillar /dum/ to fence /aru/ picture /urpati/ a riot /ɡuri/ to move /t hu/ to sleep /uk ɔ/ yonder /muluk/ an area /su/ to measure

Table. 2.1.4.3 (d): Examples of the occurrence of phoneme /u/ .

2.1.5 The second parametric classification of the Kokborok vowels Kokborok has three degrees of vowel height which may be termed as high, mid, and low. The high vowels in Kokborok are /i, ɯ, u /. The mid vowels are /e, ə, ɔ, o/. The low vowel is /a/ . All the vowels except / ə, o/ occur in all word positions. The vowel / ə/ always occurs only in the medial position of words. The vowel /o/ occurs in the medial and final positions. Vowel contrasts are found in all the positions of a Kokborok word. They can contrast in word initial, medial and final positions.

Chapter 2: Phonological Sketch of the Kokborok Language

The following Tables 2.1.5 (a), (b) and (c) present vowel contrasts initially, medially and finally. Initial vowel word gloss /ik/ roast /i/ vs /e/ /ek/ stir /a ŋ/ I /a/ vs /ɯ/ /ɯŋ / to be /ɔrɔ/ here /ɔ/ vs /a/ /ar ɔ/ that /ib ɔ/ it /i/ vs /ɔ/ /ɔbɔ/ this /ari/ border /a/ vs /i/ vs /u/ /iri/ co-wife /uri/ a white ant

Table : 2.1.5 (a) Contrast in word initial position.

Medial vowel word gloss /jak/ hand /a/ vs /o/ /jok/ pungent /s ɯk/ to tight /ɯ/ vs /ə/ vs /ɔ/ /s ək/ the body /s ɔk/ to rot /bera/ to keep /e/ vs /ə/ vs /ɔ/ /b əra/ five hundred /b ɔra/ a round bread of Boroks /mil/ plain land /i/ vs /e/ vs /a/ /mel/ function /mal/ the Mercury /rak/ to hard /rik/ art /a/ vs /i/ vs /u/ vs /ruk/ to boil /ɯ/ vs /ɔ/ /r ɯk/ to chase away /r ɔk/ plural marker Table : 2.1.5 (b) Contrast in word medial position.

Chapter 2: Phonological Sketch of the Kokborok Language

Final vowel word gloss /ri/ cloth /i/ vs /ɯ/ vs /u/ /r ɯ/ to give /ru/ one kind of animal /se/ to replace /sa/ to speak /e/ vs /a/ vs /ɔ/ vs /s ɔ/ to close /o/ vs /i/ vs /u/ /so/ to pull /si/ to know /su/ to measure Table : 2.1.5 (c) Contrast in word final position.

2.1.6 The spectrographic sketch of the Kokborok vowels As discussed in the introduction of this chapter there is a relatively simple correspondence between tongue height, tongue frontness and backness and the relative positions of first formant (f 1) and second formant (f 2). The first formant (f 1) relates to the vowel height and the second formant (f 2) relates to vowel frontness and backness and lip rounding. The spectrographic sketch of all the eight (8) Kokborok vowels given in the following Figure 2.1.6 is showing the relation between (a) vowel height and first formant (f 1) and (b) vowel frontness, backness, lip roundings and second formant (f 2).

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.1.6 Waveforms and spectrograms of the Kokborok eight (8) vowels.

The spectrogram shows that the Kokborok high vowels - /i/ , /ɯ/ and /u/ have a low f 1. The f 1 of low vowel - /a/ is higher in comparison to high vowels. The Kokborok front vowels - /i/ and /e/ have a high f 2 but the back vowels - /ɔ/, /o/ and /u/ have low f 2. The spectrogram also shows that the lip rounding lowers the f 2. The second formant (f 2) gets progressively lower as the Kokborok vowels move from front to central to back.

2.1.7 The formant frequency values of the Kokborok vowels The utterances such as {/mil, m el, m al, m əla, m ɯlɯk, m ɔhl, m ol, muluk/} are used for the formant frequency measurement of the Kokborok eight vowels. For the acoustic description of the Kokborok vowels, the formant frequency is measured in Hertz. For the actual acoustic measurements of the Kokborok vowels, numbers are used. The results of a detailed spectrographic study on the formant frequency of vowels in Kokborok are given in the Table 2.1.7. For the acoustic measurement, the concentration is given on the formant frequency of the Kokborok vowels recorded in words medially in order to get the exact formant frequency values. The table shows

Chapter 2: Phonological Sketch of the Kokborok Language

the frequency values of f 1 and f 2 of the Kokborok Vowels together with the negative values of formant frequency.

Frequency (Hz) SL Vowel Word Gloss f1 f2 Mns (f 2-f1) Mns f 1 1 i mil plain land 265 2394 -2129 -265 2 e mel function 486 2184 -1698 -486 3 a mal the Mercury 651 1760 -1109 -651 4 ə məla sterile 475 1555 -1080 -475 5 ɯ mɯlɯk hiccough 295 1264 -969 -295 6 ɔ mɔhl the season 564 955 -391 -564 7 o mol long duration 461 856 -395 -461 8 u muluk an area 262 708 -446 -262

Table 2.1.7: Formant frequency (in Hz) values of f 1 and f 2 of the Kokborok Vowels.

The frequency values of f 1 and f 2 – as given in Table 2.1.7 above are represented graphically in Figure 2.1.7. In the following figure, the vertical axis shows the formant frequency in Hz and the horizontal axis lists the vowels along with their formant frequency values.

Figure 2.1.7: The formant frequency values of f1 and f2 of the Kokborok vowels and their positions.

Chapter 2: Phonological Sketch of the Kokborok Language

The Table 2.1.7 and the Figure 2.1.7 exhibit that the formant frequency values of all the Kokborok vowels are varied from each other. The variations are in such a way that the front vowels are having high f 2 but back vowels are having low f 2. The f 1 and f 2 are far apart in front vowels but f 1 and f 2 are close together in back vowels. For central or neutral vowels, formant values are nearly at equidistance. The chief cause of the variation in the formant frequency values is the variation in the size and shape of the degree of constriction in the vocal tract.

2.1.8 The Kokborok vowel quadrilateral The results of a detailed spectrographic study on the frequency of vowels in Kokborok are given in the Table 2.1.7. The table shows the frequency values of f 1 and f 2 of the Kokborok Vowels together with the negative values of frequency.

As we know, the f 1 deals with vowel height and f 2 deals with vowel frontness and backness. The negative frequency values of f 1 and f 2 of the Kokborok vowels given in the Table 2.1.7 are charted in the Figure 2.1.8. The negative values are plotted in the following figure against the bold dots indicating the positions of the Kokborok vowels → {/i, e, a, ə, ɯ, ɔ, o, u /}.

Further, in the same figure the f 1 frequency for all the vowels is plotted on the vertical axis and the f 2 frequency on the horizontal axis.

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.1.8: The vowel quadrilateral showing the formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels.

2.1.9 The Kokborok Diphthongs Like many other languages, Kokborok has some vowel segments whose resonance or formant frequency is not constant. That is to say, it changes continually while the vowel is being uttered. The technical term for a vowel of continually changing resonance or formant frequency is a ‘diphthong’. Kokborok has four such diphthongs – i.e. / ai/ , /ɔi/ , /au/ , and /ua/ and all of them are phonologically distinctive. The following are the spectrographic sketch of all the Kokborok diphthongs.

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.1.9 Waveforms and spectrograms of the Kokborok four (4) diphthongs.

Diphthongs can be described and identified in terms of their beginning and ending points, which form a glide within one and the same syllable. Most of the stress associated with these diphthongs is concentrated on the first element whereas the second element is only lightly sounded. However, the spectrogram displays that all the diphthongs while articulated are gliding and changing their formant frequency pattern. The Kokborok diphthong such as /ai/ represents /a/ as starting or onglide element and /i/ as ending or off-glide element. The spectrogram exhibits that the formant pattern of onglide and offglide of each diphthong is varied from each other. An outline of the variation of each element of Kokborok diphthongs is given in the following:

• The diphthongs such as /ai/, / ɔi/ and /ua/ show that the f 1 and f 2 of the

onglide are close together and the f 1 and f 2 of the offglide are far apart from each other.

• But the diphthong /au/ shows that the f 1 and f 2 of the onglide are far apart

and the f 1 and f 2 of the offglide of this diphthong are close together. 59

Chapter 2: Phonological Sketch of the Kokborok Language

The main reason of the variations in the formant pattern is the gildings in the diphthong. And the gilding is the changing of the resonances or formant frequencies in the vocal tract. The phonemic description of the Kokborok four diphthongs are in the following:

/ai/ For the articulation of Kokborok /ai/, the mouth remains in a position between half close and half open. The tongue glide begins at a central position, and then moves in the direction of Kokborok /i/, there being a slight closing movement of the lower jaw. The lips change from a neutral to a loosely spread position. It occurs in all the three positions such as initial, medial and final. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /aik hɔr/ letter /k hain/ spot /p hai/ to come /ait ɔrma/ morning star /hain ɔ/ unnecessry /mai/ rice /ain/ law /hai čhiŋ/ ginger /snai/ beyond

Table. 2.1.9 (a) : Examples of the occurrence of diphthong /ai/ .

/ɔi/

For the production of Kokborok / ɔi/ the mouth remains at a point between half open and half close. The tongue glide begins at a back position, and moves towards the direction of Kokborok /i/. There being a slightly opening movement of the lower jaw. The lips change from round to a loosely spread position. It occurs in all word positions. For example

Initial Medial Final Word Gloss Word Gloss Word Gloss /ɔi/ fine /ǰɔ iɡɔ / wastage /t ɔi/ aunt /ɔine/ very hard /s ɔisima ŋ/ science /k ɔi/ to request Table. 2.1.9 (b) : Examples of the occurrence of diphthong /ɔi/ .

Chapter 2: Phonological Sketch of the Kokborok Language

/au/

For the production of Kokborok /au/, the mouth position remains between half close and half open. The tongue glide begins at a central position, and then moves in the direction of Kokborok /u/, there being a slightly closing movement of the lower jaw. The lips are neutral for the first element, i.e. for /a/ but they have a tendency to round on the second element, /u/. It occurs in all word positions. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /auli/ town /haua ŋ/ condition /t hau/ oil /aua ŋ/ bread /bauti/ Borok ornaments /mau/ to shoot

Table. 2.1.9 (c) : Examples of the occurrence of diphthong /au/ .

/ua/ For the articulation of Kokborok /ua/, the mouth position remains between half close and half open. The tongue glide begins at a back position, and then moves in the direction of Kokborok /a/, there being a slightly opening movement of the lower jaw. The lips are rounded for the first element, i.e. for /u/ but they are neutral for the second element, i.e. for /a/. It occurs in all word positions. For example

Initial Medial Final Word Gloss Word Gloss Word Gloss /uak/ pig /kuak/ broken /kua/ a well /uar/ praiseworthy /suar/ wisdom /dua/ a fruit /uak čhɔ/ pieces of bamboo /čhuak/ wine /uakelua/ molar tooth

Table. 2.1.9 (d) : Examples of the occurrence of diphthong /ua/ .

Chapter 2: Phonological Sketch of the Kokborok Language

2.1.10 The Kokborok Triphthong Triphthong is a single vocalic nucleus which begins with one vowel, moves to a second quality, and then finishes with a third quality (Trask, 1996). Kokborok has only one triphthong of such type i.e. - /uai/ . The spectrographic representation of the Kokborok triphthong is in the following:

Figure 2.1.10 Waveform and spectrogram of the Kokborok triphthong.

The spectrogram shows that the each element such as onglide (starting), nuclei (mid) and offglide (ending) of the Kokborok triphthong / uai/ is changing while gliding from one to another. The changes are in such a way that the distance between f 1 and f 2 of the first element /u/ is closer, the distance between f 1 and f 2 of the second element /a/ is next higher and the distance between f 1 and f 2 of the third element /i/ is highest. The chief cause of the changing is the changing of resonance or formant frequencies in the vocal tract. The phonemically triphthong is a single sound (speech sound) which has starting and ending point via some other, third, vowel in the middle.

Chapter 2: Phonological Sketch of the Kokborok Language

The Kokborok triphthong occurs in all the positions. For example:

Initial Medial Final Word Gloss Word Gloss Word Gloss a ploughed /uai ŋ/ the gum /čhuaiha/ /čhuai/ to plough field to visit /uaiklai/ /čhuaik ɔl/ tractor /kuai/ betel nut relative brother in /uaikre/ fruit /buai ǰɯ k/ sister in law /nuai/ law

Table. 2.1.10 : Examples of the occurrence of triphthong /uai/ .

Chapter 2: Phonological Sketch of the Kokborok Language

Part-II : Consonants

2.2.1 Introduction Consonants are sounds made by a closure or narrowing in the vocal tract so that the air flow is either completely blocked or so restricted that some audible friction is produced. Consonant articulations are relatively easy to feel, and as a result are most conveniently described in terms of place and manner of articulation (Crystal, 2003). From a phonological point of view, consonants are those units which function at the margin of syllables, either singly or in cluster (Crystal, 2003). The present section gives an account of phonemic inventory of the Kokborok consonant phonemes. This section also looks into all types of phonologically distinctive consonant sounds in Kokborok and puts forward their spectrographic sketch, description, classification and phonemic analysis.

2.2.2 Phonemic inventory of the Kokborok consonants For the convenience of phonemic inventory, the sufficient data has been recorded and transcribed phonetically. Based on the data the following table is prepared. This table lists the consonant phonemes which are found in the Kokborok language.

Chapter 2: Phonological Sketch of the Kokborok Language

The Kokborok Consonants: Labial Coronal Dorsal Places of articulation → Glottal Bilabial Alveolar Palatal Velar Manners of articulation ↓ Unaspirated p t k Voiceless

Aspirated ph th čh kh Stops

Voiced Unaspirated b d ǰ ɡ

Obstruents Obstruents

Fricatives Voiceless s h

Nasals Voiced m n ŋ

Lateral l Approxim Voiced Sonorants Sonorants ants Central r j

Table 2.2.2 The Kokborok consonant phonemes.

2.2.3 Classification of the Kokborok consonants The consonant whose articulation involves an obstruction in the vocal tract to produce friction noise is termed as obstruent and the segment which is produced with free airflow and spontaneous vibration of vocal folds is termed as sonorant . Like other languages, the consonants of Kokborok can be classified into (a) obstruents – i.e. {/p, p h, b, t, t h, d, čh, ǰ, k, k h, ɡ, s, h, /} and (b) sonorants – i.e. {/m, n, ŋ, r, l, j/}. Further, the obstruent consonants can be classified into different sets – i.e. (i) voiceless unaspirated stops {/p, t, k/}, (ii) voiceless aspirated stops {/p h, t h, čh, k h/}, (iii) voiced stops {/b, d, ǰ, ɡ/} and (iii) fricatives {/s, h/}. The sonorant consonants can also be classified into different sets – i.e. (i) nasals {/m, n, ŋ/} and (ii) approximants {/r, l, j/}.

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Chapter 2: Phonological Sketch of the Kokborok Language

2.2.3.1 The Voiceless Unaspirated Stops Kokborok has three voiceless unaspirated stops – i.e. {/p, t, k/}.

Stops refer to any speech sound which is produced by a complete closure in the vocal tract, and thus traditionally includes the class of plosives (Crystal, 2003).The complete articulation of stop consonants consists of three stages: (1) the Closing (2) the Holding and (3) the Release stage. In accordance with the closure in the vocal tract the Kokborok voiceless unaspirated stops can be grouped into the following table:

Places → Labial Coronal Dorso-velar Manner ↓ Stops Unaspirated p t k

Table 2.2.3.1 The Kokborok voiceless unaspirated stops. The spectrographic sketch of the Kokborok voiceless unaspirated stops – {/p, t, k/} as in the words /apa/ (father), /ata/ (brother) and /akar/ (greedy) is in the following:

Figure 2.2.3.1 : Waveforms and spectrograms of the Kokborok voiceless unaspirated stops in /apa/ , /ata/ and /akar/ .

Chapter 2: Phonological Sketch of the Kokborok Language

The Kokborok voiceless unaspirated stops – {/p, t, k/} are realized with the closure. The blank space in the above waveform and gap in the spectrogram indicate the region of voiceless unaspirated stop sounds. The blank space in the waveform and gap in the spectrogram correspond to the closure of the articulators in the vocal tract and the voicelessness. For the sound /p/ the lower lip and upper lip contact each other and make the closure. For the sound /t/ the tip of the tongue contacts the alveolar ridge and makes the closure. For the sound /k/ the dorsum of the tongue contacts the velum and makes the closure. All the three voiceless unaspirated stops /p/ , /t/ and /k/ occur in all word positions - initial, medial and final. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /p ɔhɔr/ light /harpek/ clay /k ɔlɔp/ to cover /t ɔŋ / to remain /balte ŋ/ bucket /kat/ scarcity /kah ŋ/ thirsty /čhakur/ knife /ban ɔk/ to make Table. 2.2.3.1 : Examples of the occurrence of Kokborok voiceless unaspirated stops {/p, t, k/}.

2.2.3.2 The Voiceless Aspirated Stops Kokborok has four voiceless aspirated stops – {/p h, t h, čh, k h/}. In accordance with the closure in the vocal tract the Kokborok voiceless unaspirated stops can be grouped into the following table: Places → Labial Coronal Dorso-palatal Dorso-velar Manner ↓ Stops Aspirated ph th čh kh Table 2.2.3.2 The Kokborok voiceless aspirated stops.

The spectrographic sketch of the Kokborok voiceless aspirated stops – {/p h, t h, čh, k h/} as in the words /ap ha/ (my father), /at haŋ/ (insane), /ka čha/ (to rise) and /ak hata/ (curry) is in the following:

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.2.3.2 : Waveforms and spectrograms of the Kokborok voiceless aspirated stops in /ap ha/, /at haŋ/, /ka čha/ and /ak hata/ .

Chapter 2: Phonological Sketch of the Kokborok Language

The Kokborok voiceless aspirated stops – {/p h, t h, čh, k h/} are realized with the closure followed by a short burst of noise. The blank space and the noise burst in the above waveform and gap and spike in the spectrogram indicates the region of the voiceless aspirated stop sounds. The blank space and noise burst in the waveform and gap and spike in the spectrogram correspond to the duration of the articulators in the vocal tract and the voicelessness. The sound /p h/ is made with the contact of lower lip and upper lip. The tip of the tongue contacts the alveolar ridge to make the sound /t h/. The tongue dorsum contacts the hard palate to make the sound /čh/. The dorsum of the tongue contacts the velum to make the sound /k h/. The sounds {/p h, t h, k h/} are made with the same gestures of articulators as the sounds {/p, t, k/} are made. All the four voiceless aspirated stops - /p h/, /t h/, / čh/ and /k h/ occur only in word initial and medial positions. For example: Initial Medial Final Word Gloss Word Gloss /p hal/ to sell /d əpha/ a kind of paddy /t haŋ/ to go /k ɔthɔr/ the ice No occurrence /čhak/ to read /a čhuk/ to sit /k hati/ savings /ǰalk hal/ restless

Table. 2.2.3.2 : Examples of the occurrence of Kokborok voiceless aspirated stops {/p h, t h, čh, k h/}.

2.2.3.3 The Kokborok Voiced Stops Kokborok has four voiced stops – {/b, d, ǰ, ɡ/}. In accordance with the closure in the vocal tract the Kokborok voiced stops are presented in the following table: Places → Labial Coronal Dorso-palatal Dorso-velar Manner ↓ Stops Voiced b d ǰ ɡ Table 2.2.3.3 Kokborok voiced stops.

Chapter 2: Phonological Sketch of the Kokborok Language

The spectrographic sketch of the Kokborok voiced stops – {/b, d, ǰ, ɡ/} as in the words /haba/ (place of work), /hada/ (tobacco), /ra ǰa/ (king) and /a ɡar/ (hole of fish) is in the following:

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.2.3.3 : Waveforms and spectrograms of the Kokborok voiced stops in /haba/ , /hada/ , /ra ǰa/ and /a ɡar/ .

The Kokborok voiced stops – {/b, d, ǰ, ɡ/} are realized with the closure followed by the sharp beginning of formant structure. The decreasing of amplitude in the above waveform and sharp beginning of formant structure near the base line called ‘ voice bar ’ of the spectrogram indicate the region of voiced stop sounds. The vertical striations in the voice bar of the spectrogram correspond to the opening and closing of the vocal folds. The opening and closing of the vocal folds cause the vibration and the voicing. For the sound /b/ the lower lip and upper lip contact each other and make the closure. For the sound /d/ the tip of the tongue contacts the alveolar ridge and makes the closure. For the sound /ǰ/ the tongue dorsum contacts the hard palate and makes the closure. For the sound /ɡ/ the dorsum of the tongue contacts the velum and makes the closure. The sounds {/b, d, ɡ/} are made with the same gestures of articulators as the sounds {/p h, t h, k h/} and {/p, t, k/} are made.

Chapter 2: Phonological Sketch of the Kokborok Language

The voiced stops /b/ , /d/, / ǰ/ occur in word initial and medial positions only but the /ɡ/ occurs in all the three positions. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /ban ɔk/ to make /kebe ŋ/ the breath No occurrence /d ɔɡ i/ to order /haduk/ a road

/ǰɔŋ / servant /a ǰɔŋ / that side /ɡɔŋ / the bear /ǰuɡali/ helper /ba ɡ/ section

Table. 2.2.3.3 : Examples of the occurrence of Kokborok voiced stops {/b, d, ǰ, ɡ/}.

2.2.3.4 The Kokborok Fricatives Kokborok has two fricatives sounds – {/s, h/}.

The term ‘fricative’ refers to consonant sounds that are made when two speech organs come so close together that the air moving between them produces audible noise or friction. There is no complete closure between the organs: there is simply a stricture or narrowing of the organs (Crystal, 2003). In accordance with the noise or friction in the vocal tract the Kokborok fricatives can be shown as follows: Places → Coronal Glottal Manner ↓ Fricatives s h

Table 2.2.3.4 The Kokborok fricatives.

The spectrographic sketch of the Kokborok fricatives – {/s, h/} as in the words /kasa/ (to climb) and /kaham/ (good) is as follows:

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.2.3.4 : Waveforms and spectrograms of the Kokborok fricatives in /kasa/ and /kaham/ .

The Kokborok fricatives – {/s, h /} are realized with the noise or friction. It may be noticed that there is random decreasing of amplitude in above the waveform and the noise pattern (in the form of a fuzzy patch ) in higher frequency region of the spectrogram. This indicates the region of fricative sounds. The random energy concentration in the waveform and the noise pattern in the higher frequency region of the spectrogram correspond to the turbulence through the vocal tract and the voicelessness. For the sound /s/ the side rims of the tongue make a contact with the upper side teeth. The air flows through the centre of the tongue and causes friction and the friction is without causing vibration in the vocal folds. For the sound /h/ the air is expelled from the lungs and passed through the open glottis with considerable pressure, causing some audible friction in the vocal tract, therefore /h/ is referred to as a voiceless glottal fricative.

Chapter 2: Phonological Sketch of the Kokborok Language

These fricatives occur in word initial, medial and final positions. For example: Initial Medial Final Word Gloss Word Gloss Word Gloss /sam/ grass /d ɔsa/ danger /has/ to start /ham/ to be good /sahar/ to scatter /pah/ all or entire Table. 2.2.3.4 : Examples of the occurrence of Kokborok fricatives {/s, h/}.

2.2.3.5 The Kokborok Nasals Kokborok has three nasal sounds – i.e. {/m, n, ŋ/}.

The term ‘nasal’ refers to those speech sounds that are produced while the soft palate is lowered to allow an audible escape of air through the nose. Both the consonants and vowels may be articulated in this way. Nasal consonants occur when there is a complete closure in the mouth, and all the air escapes through the nose (Crystal, 2003). In accordance with the closure in the vocal tract the Kokborok nasals can be shown in the table as follows: Places → Labial Coronal Dorso-velar Manner ↓ Nasals m n ŋ

Table 2.2.3.5 The Kokborok Nasals.

The spectrographic sketch of the Kokborok nasals – {/m, n, ŋ/} as in the words /lama/ (path), /lana/ (to take) and /la ŋa/ (basket) is given below:

Chapter 2: Phonological Sketch of the Kokborok Language

Figure 2.2.3.5 : Waveforms and spectrograms of the Kokborok nasals in /lama/ , /lana/ and /la ŋa/ .

The Kokborok nasals-{/m, n, ŋ/} are realized with the closure followed by voicing. The decreasing of amplitude in the above waveform and the faint region in the spectrogram indicate the region of nasal sounds. The area of nasal sounds in the spectrogram is fainter because of additional nasal resonance also called anti-formants. The arrowheads in the spectrogram indicate the low intensity. It corresponds to the loss of acoustic energy and the estimated anti-formant reign of the nasal sounds. For the sound /m/ the lips form a closure as that for /p, b/; the velum is lowered and the oral cavity is closed by the lips. As a result the audible air escapes through nasal cavity. For the sound /n/ the tip of the tongue contacts alveolar ridge and form a closure as that for /t, d/; the velum is lowered and the oral cavity is closed by the tip of the tongue and alveolar ridge. As a result the audible air passes through nasal cavity. For the sound /ŋ/ the tongue dorsum and the velum form a closure as that for /k, ɡ/; the velum is lowered shutting the oral cavity. As a result the audible air escapes directly through nasal cavity. The vertical striations of the

Chapter 2: Phonological Sketch of the Kokborok Language region of the nasal sounds in the spectrogram correspond to the vibration of the vocal folds during the articulation of {/m, n, ŋ/}. Both /m/ and /n/ occur in all the three positions of word but /ŋ/ occurs only in medial and final positions. For example:

Initial Medial Final Word Gloss Word Gloss Word Gloss to be /ma ɡna/ free of cost /k ɔkma ŋ/ meaning /čham/ destroyed /na ŋ/ need /k ɔkna/ to obey /ke čhen/ defeated No occurrence /ba ŋla/ earthquake /k heŋ/ to free Table. 2.2.3.5 : Examples of the occurrence of Kokborok nasals {/m, n, ŋ/}.

2.2.3.6 The Kokborok Approximants Kokborok has three approximants – {/r, l, j/}.

Phoneticians like Ladefoged (1971) used the term ‘approximant’ to refer to a consonant sound on the basis of its manner of articulation; Abercrombie (1967) and Gimson (1970) called the same sound as ‘frictionless continuant’. In other words the term ‘approximants’ refers to those speech sounds that are produced with the narrowing of articulators at some points in the vocal tract without making a closure or friction. The Kokborok approximants can be classified into (i) central and (ii) lateral. These may be shown in the table as follows: Places → Coronal Dorso-palatal Manner ↓ Lateral l Approximants Central r j Table 2.2.3.6 The Kokborok approximants.

Chapter 2: Phonological Sketch of the Kokborok Language

The spectrographic sketch of the Kokborok approximants – {/r, l, j/} as in the words /kara/ (jokes), /kalam/ (step) and /aja ŋ/ (that side) is given below:

Figure 2.2.3.6 : Waveforms and spectrograms of the Kokborok approximants in /kara/ , /kalam/ and /aja ŋ/.

The approximants – {/r, l, j/} are realized with the articulatory organs approaching each other without closure or friction. The articulatory process of approximants is almost opposite to that of stops. The slight decreasing of amplitude in the above waveform and the faint region in the spectrogram indicate the region of approximant sounds. The faint regions of the spectrogram correspond to the consonants that have the vowel like articulations. In the articulation of sound /r/ the tip of the tongue contacts a point on the roof of the mouth, that is just behind the upper front teeth. For the sound /l/ the tip of the tongue touches the upper teeth or roof of the mouth as for / t, d/ allowing the air to escape freely by both sides of the tongue. For the sound /j/ the front of the tongue is raised to an approximate extent that is not enough to make a closure or hinder the airflow. The vertical striations of the

Chapter 2: Phonological Sketch of the Kokborok Language region of approximant sounds in the spectrogram correspond to the vibration of the vocal folds during the articulation of {/r, l, j/}. Both /r/ and /l/ occur in all the three positions of word but /j/ occurs only in initial and medial positions. For example:

Initial Medial Final Word Gloss Word Gloss Word Gloss /ra ŋ/ rupee /harkel/ lamp /andar/ dark /la ŋta/ naked /hal ɔk/ relation /k hal/ to restrict

/j ɔŋ la/ a frog /bijal/ scarcity No occurrence

Table. 2.2.3.6 : Examples of the occurrence of Kokborok approximants {/r, l, j/}.

2.2.4 The contrast in Kokborok phonemes The sounds having the same place of articulation are labelled as ‘homorganic’ . The sets of Kokborok homorganic sounds are given in the table below: Labial Alveolar palatal velar Place → vl vd vl vd vl vd vl vd Unaspirated p b t d ǰ k ɡ Stops Aspirated ph th čh kh

Lateral l Approximants Central r

Table. 2.2.4 : The sets of Kokborok homorganic sounds.

Chapter 2: Phonological Sketch of the Kokborok Language

The contrast of Kokborok homorganic sounds are found in all position. They can contrast in word initial, medial and final position. The following Table 2.2.4 (a) shows the contrast in initial, medial and final positions. Initial Consonant Phonemes word gloss /pal/ a companion h /p/ vs /p / vs /b/ /p hal/ to sell /bal/ to carry /tal/ the moon /t/ vs /t h/ vs /d/ /t hal/ the Neptune /dal/ plus /čham/ to be destroyed /čh/ vs /ǰ/ /ǰam/ small size dish /kap/ to weep h /k/ vs /k h/ vs /ɡ/ /k ap/ an anchor /ɡap/ a colour /ram/ thin /r/ vs /l/ /lam/ way Medial /kait ɔr/ the God /t/ vs /t h/ /kait hɔr/ a pen /akar/ greedy /k/ vs /ɡ/ /a ɡar/ hole of fish /d əpa/ pipe h /p/ vs /p / vs /b/ /d əpha/ a kind of paddy /d əba/ smoking pipe /p hara/ a piece /r/ vs /l/ /p hala/ a bad time Final /bak/ part /k/ vs /ɡ/ /ba ɡ/ section /mar/ very much /r/ vs /l/ /mal/ the Mercury

Table : 2.2.4 (a) Contrast in initial, medial and final positions.

Chapter 2: Phonological Sketch of the Kokborok Language

The sounds having the different places of articulation are labelled as ‘heterorganic’ . The Kokborok heterorganic sounds can contrast in different word positions. The following Table 2.2.4 (b) shows the contrast in word initial, medial and final positions. Initial Consonant Phonemes word gloss /s ɔr/ iron /s/ vs /h/ /h ɔr/ night /ǰaɡra/ adult /ǰ/ vs /j/ /ja ɡra/ right side /muk/ source /m/ vs /n/ /nuk/ to see Medial /kasa/ to climb /s/ vs /h/ /kaham/ good /a ǰaŋ/ side /ǰ/ vs /j/ /aja ŋ/ that side /lama/ path /m/ vs /n/ vs /ŋ/ /lana/ to take /la ŋa/ basket Final /pas/ to start /s/ vs /h/ /pah/ entire /ham/ to be good /m/ vs /n/ vs /ŋ/ /han/ flesh /ha ŋ/ roast

Table : 2.2.4 (b) Contrast in initial, medial and final positions.

2.2.5 The articulatory sources of the Kokborok speech sounds The spectrographic sketches of all the Kokborok speech sounds are minutely observed here. Our observation finds that some sounds have regular vertical striations in their spectrograms and some do not have. The regular vertical striations in spectrograms correspond to the regular vibration of the vocal folds. The sounds that have regular vibration of the vocal folds are periodic and that do not have are aperiodic. Some Kokborok speech sounds 80

Chapter 2: Phonological Sketch of the Kokborok Language have both periodic and aperiodic quality. On the basis of the spectrographic analysis of the Kokborok speech sounds, the Table 2.2.5 is prepared which is as following:

Source Sounds Manner Phonemes Vowels /i , e , a , ə , ɯ , ɔ, o , u/ Diphthongs /ai/, / ɔi/, /au/, /ua/ Vocal folds Periodic Triphthong /uai/ Nasals /m, n, ŋ/ Approximants /r, l, j/ Voiceless /p, t, k/ unaspirated stops Voiceless Vocal tract Aperiodic /p h, t h, čh, k h/ aspirated stops Fricatives /s, h/ Vocal folds Mixed periodic Voiced stops /b, d, ǰ, ɡ/ and vocal tract and aperiodic Table 2.2.5 : The Kokborok speech sound sources.

The Table 2.2.5 shows that the source of articulation of the Kokborok Vowels, Diphthongs, Triphthong, Nasals, Approximants are the vocal folds and they are periodic. The source of articulation of the Kokborok voiceless unaspirated stops, voiceless aspirated stops, fricatives are the vocal tract and they are aperiodic. The source of articulation of the Kokborok voiced stops is both the vocal folds and vocal tract and they are mixed, periodic and aperiodic.

Chapter 2: Phonological Sketch of the Kokborok Language

2.2.6 Tones in Kokborok Kokborok is a tonal language. The tones are phonemic. There are two tonemes in this language: level (normal) and high. Level (normal) tone is as usual, but for high tone /h/ phoneme is used in a particular syllable. For example: Tone Level (normal) High Word Gloss Word Gloss /čha/ right /čhah/ to eat /lai/ easy /laih/ crossed /p hai/ to come /p haih/ to break /b ɔr/ senseless /b ɔhr/ to plant /h ɔr/ night /h ɔhr/ to send

Table 2.2.6 : Examples of Kokborok Tones.

For this study, however, tones are not further analysed.

2.2.7 Findings

This study finds that Kokborok has totally eight (8) phonologically distinctive vowel phonemes and nineteen (19) consonant phonemes. There are four (4) diphthongs; three of them are closing diphthongs – i.e. {/ai , ɔi, au/ } and one is centering diphthong – i.e. {/ua/ }. A triphthong – i.e. {/uai/ } is also found in Kokborok.

It is noted that the eight vowel phonemes and four diphthongs and a triphthong exist in word initial, medial and final positions except the vowel /ə/ and /o/ . The vowel /ə/ is restricted only in word medial position. The vowel /o/ is restricted only in word medial and final positions. All the eight Kokborok vowels have the contrast in word initial, medial and final positions except the vowel /ə/ and /o/ . The vowel /ə/ shows contrast only in medial position. The vowel /o/ exhibits contrast only in word medial and final positions.

Chapter 2: Phonological Sketch of the Kokborok Language

It is also noted that the Kokborok nineteen consonant phonemes are articulated from five different places of articulation: bilabial, alveolar, palatal, velar and glottal and from four different manners of articulation: stop, fricative, nasal and approximant. This study classifies the Kokborok stops into three sets: (i) the voiceless unaspirated stops, (ii) the voiceless aspirated stops and (iii) the voiced stops. The voiceless unaspirated stops have aspirated counterparts but voiced aspirated counterparts are non-existent in Kokborok. The voiceless palatal aspirated stop - /čh/ has no unaspirated counterpart in the language. All the nineteen consonant phonemes occur in word initial, medial and final positions except the aspirated stop consonants {/ph, th, čh, kh /} and {/b, d, ǰ, ŋ and j /}. The occurrence of consonant phonemes {/ph, th, čh, kh /} and {/b, d, ǰ, j, /} is limited to the word initial and medial positions. However, the phoneme / ŋ/ occurs in the word medial and final positions. All the Kokborok homorganic consonant phonemes show contrast in word initial position but a few have contrast in the medial position and still few have contrast in the final position. The spectrographic sketches of all the Kokborok phonemes given in the chapter show that the acoustic cues of all the Kokborok sounds are distinguishable from one another.

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Chapter 3 : Acoustic Analysis of the Kokborok Vowels ______

3.0 Overview The present chapter deals with the acoustic analysis of the Kokborok vowel. For the convenience of the study it is divided into two parts. Part one deals with the acoustic analysis of the Kokborok vowels and part two deals with the analysis of the Kokborok diphthongs and triphthong. In both the parts numerical analysis of the Kokborok vowel, diphthongs and triphthong is given. The chapter also gives variation of formant frequency and duration. Finally, the chapter gives the findings of overall acoustic analysis of the Kokborok vowels.

Part I: Vowels

3.1.1 Introduction The spectrograms of speech represent a visual display that shows the frequency dimension horizontally, while the intensity is used by varying degrees of darkness - depending on the source. For acoustic analysis of a vowel segment, the LPC based signal processing is used. For this study it is felt convenient to use the broad band analysis. This is because this type of analysis is very helpful for the analysis of segmental phonemes. ‘The formant structures are the regions of energy concentration’ (Truby, H. M. et al, 1960). These formants appear horizontally starting at the bottom of the spectrograms and are called formant one (f 1), formant two (f 2) and formant three (f 3) etc and are measured in Hertz (Hz). There are more formants. But only the first three formants are important for the analysis of a vowel.

87 Chapter 3: Acoustic Analysis of the Kokborok Vowels

3.1.2 Method The method comprises a description of participants, stimuli and procedure used to study Kokborok vowels acoustically.

3.1.2.1 Participants In total forty (40) Kokborok speakers participated. They include fifteen (15) men, fifteen (15) women and ten, twelve to fifteen years old children (5 boys and 5 girls). All of them are native speakers of Kokborok and they belong to Tripura. All of them are multilingual. All of them had not received any phonetic training and knowledge of this kind of experiments.

3.1.2.2 Stimuli The stimuli contain thirty one (31) tokens of Kokborok vowels in isolation, in words and connected speech.

3.1.2.3 Procedure For the acoustic analysis of Kokborok vowel phonemes, audio recording of men, women and children are made. The recordings of eight (8) vowels, four (4) diphthongs and a triphthong are done with atleast three reading of each token on a digital audio recorder. The speech analysis software ‘Praat’ is used to generate and draw waveforms as well as spectrograms. The first part and the last part of each of the recordings are ignored but the middle part is used for the acoustic analysis. The vowel phonemes are studied within the measurable scales or parameters of duration and formant frequency. The entire speech of informants is transcribed and presented in the form of broad transcription made in International Phonetics Alphabet. For the acoustic measurements of the Kokborok vowel phonemes the numerics are used. The spectrograms and the waveforms are examined very carefully on personal computer (PC) for the

Chapter 3: Acoustic Analysis of the Kokborok Vowels measurements of the vowel phonemes and then the mean value of the numbers of the sounds is taken and represents them graphically.

3.1.3 Results and discussion For systematic presentation of the results of this acoustic study as well as our discussions on these results, the contents of this chapter are divided into two parts. In the first part we deal with the vowels in Kokborok; in the second, we deal with its diphthongs and triphthong as well. The results of the vowels are stated and discussed under the relevant headings, which are as follows:

3.1.3.1 Duration measurement of the Kokborok vowels The duration measurements of all the Kokborok vowels here are done in milliseconds. The results of a detailed spectrographic study on the average duration values of vowels in Kokborok are given in the Table 3.1.3.1 . Further focus here is on the duration of the Kokborok vowels recorded in isolation, in words and in connected speech. The words and utterances used for duration measurement of vowels {/i, e, a, ə, ɯ, ɔ, o, u/} are - {/mil, mel, mal, m əla, mɯlɯk, m ɔhl, mol, muluk/} and {(i) /b ɔ belai biɡra/ (ii) /ani m əmla kɯrɯi/ (iii) /b ɔnɔ sadi ǰot ɔnɔ kubui/} respectively. The table shows average duration values (in ms) of the Kokborok Vowels, produced by 15 men 15 women and 10 children, together with the average duration of overall utterance and percentage of vowel duration within the overall utterance.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Table 3.1.3.1 : Average duration values of the Kokborok Vowels recorded in isolation, in a word and connected speech, produced by 15 men, 15 women and 10 children, together with the duration of overall utterance and percentage of vowel duration within the overall utterance. Averages are based on total number of tokens. The duration measurements are in milliseconds. (For isolated vowels, numbers of speakers are 5 men, 3 women and 2 children). Vowels In Isolation

Vowel → /i/ /e/ /a/ /ə/ /ɯ/ /ɔ/ /o/ /u/

M 246 257 276 143 228 251 236 225 Duration W 311 337 357 195 332 339 335 321 of vowel C 287 316 325 187 309 321 314 307 Vowels In Words Utterance → /mil/ /mel /mal/ /m əla/ /m ɯlɯk/ /m ɔhl/ /mol/ /m uluk/ Vowel → /i/ /e/ /a/ /ə/ /ɯ/ /ɔ/ /o/ /u/ Duration M 353 448 483 479 524 419 412 492 of overall W 421 534 558 571 598 521 501 554 utterance C 396 511 519 525 542 513 484 503

M 153 162 167 63 81 105 145 84 Duration W 224 237 258 103 112 179 202 115 of vowel C 179 198 206 98 99 156 191 102

% of vowel M 43.34 36.16 34.58 13.15 15.46 25.06 35.19 17.07 duration within the W 53.21 44.38 46.24 18.08 18.73 34.36 40.32 20.76 overall utterance C 45.20 38.75 39.69 18.67 18.27 30.41 39.46 20.28

Vowels In Connected Speech ə ɯ ɔ Utterance → / b ɔ belai biɡra / / ani m ml a k rɯi / / b nɔ sadi j otɔnɔ kubui / Vowel → ə ɯ ɔ /i/ /e/ /a/ / / / / / / /o/ /u/ Duration M 1283 1341 2409 of overall W 1345 1497 2553 utterance C 1304 1421 2501

M 86 67 156 53 112 124 144 109 Duration W 122 107 201 97 196 178 199 176 of vowel C 101 99 175 76 152 159 164 134

% of vowel M 6.70 5.22 11.63 3.95 8.35 5.15 5.98 4.52 duration within the W 9.07 7.96 13.42 6.48 13.09 6.97 7.79 6.89 overall utterance C 7.75 7.59 12.32 5.35 10.70 6.36 6.56 5.36 Table 3.1.3.1 : Average duration values and the percentage of duration of the Kokborok vowels.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

The average duration values of these vowels as recorded in isolation, in a word and connected speech produced by men, women and children as given in the Table 3.1.3.1 are plotted in Figure 3.1.3.1 (a), (b), (c) and (d).

Figure 3.1.3.1 (a) : Average duration values of the Kokborok vowels produced by men in isolation (Blue Colum), in a word (Red Colum) and connected speech (Green Colum).

Figure 3.1.3.1 (b) : Average duration values of the Kokborok vowels produced by women in isolation (Blue Colum), in a word (Red Colum) and connected speech (Green Colum).

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.1 (c) : Average duration values of the Kokborok vowels produced by children in isolation (Blue Colum), in a word (Red Colum) and connected speech (Green Colum).

The blue colums in the above figures correspond to the sounds in isolation, the red colums correspond to the sounds in words and the green colums correspond to the sounds in connected speech. These figures present a comparison amongst the men, women and children and their average duration values. The Table 3.1.3.1 and the Figures 3.1.3.1 (a), (b) and (c) show that vowels in isolation produced by men, women and children have longer durations than vowels produced in words and connected speech. These also show that /a/ has longest duration while /ə/ has shortest duration in Kokborok. Whether produced in isolation or in words or connected speech, the overall duration pattern of these vowels remains very similar. The data also show that open vowel for instance /a/ produced in isolation, in a word and connected speech by men, women and children maintains longer duration than close vowels /i/ and /u/ . It is also seen that the central vowel /ə/ has shortest duration than the other vowels in Kokborok. It is also seen that the duration of vowel /ɯ/ and /u/ is higher in isolation, lower in connected speech and the lowest in a word. But the mid-low vowel /ɔ/ produced by men and children shows

Chapter 3: Acoustic Analysis of the Kokborok Vowels longer duration in isolation, shorter in connected speech and the shortest in a word.

Figure 3.1.3.1 (d) : Average duration values of the Kokborok vowels in words produced by men (Blue Colum), women (Red Colum) and children (Green Colum).

The Table 3.1.3.1 also shows that the average vowel duration of children produced in isolation, in words or connected speech is longer than that of men and shorter than that of women. The Figure 3.1.3.1 (d) is drawn as a specimen to show all the Kokborok vowels in words produced by men have the shortest duration; children have longer duration and women have the longest duration values. However, the percentage of vowel duration within the overall utterances produced in words and connected speech by men, women and children has shown in the Table 3.1.3.1 and plotted in the Figure 3.1.3.1 (e) .

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.1 (e) : Percentage of vowel duration for men (Blue Colum), women (Red Colum) and children (Green Colum) within words and connected speech.

The table and the figure show that the percentage of the Kokborok vowels either in words or connected speech produced by women has more duration than men and children. The percentage of children is more in comparison to men except the vowel / ə/. The vowel /ə/ takes longer duration in a word in case of children.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

It may be noted from the data given in the Table 3.1.3.1 and the Figure 3.1.3.1 (e) that the duration of percentage of the Kokborok vowels produced in words by men, women and children increases in the following order: Men → { ə < ɯ < u < ɔ < a < o < e < i }, Women → { ə < ɯ < u < ɔ < o < e < a < i } and Children → { ɯ < ə < u < ɔ < e < o < a < i }.

In all the cases the vowel /i/ has the highest duration of percentage in words. In the case of men and women the sequence of percentage of vowel duration is similar except some variations in vowels {/e, a, o/}. But the sequence of percentage in words in the case of children is in such a way that generalization is difficult. The sequence of percentage in connected speech is varied in such a way the any significant generalization is not possible.

3.1.3.2 Formant frequency measurement of the Kokborok vowels In this section, the formant frequency measurements of all the Kokborok vowels are done in Hertz (Hz). The results of a detailed spectrographic study on the average formant frequency of vowels in Kokborok are given in the Table 3.1.3.2 (a), (b) and (c). Here focus is on the formant frequency of the Kokborok vowels recorded in isolation, in words and connected speech. The same utterances are used for formant frequency measurement, which is given in section 3.1.3.1 .The table shows average formant frequency (in Hz) of the Kokborok Vowels, produced by 15 men 15 women and 10 children together with the negative values of formant frequencies.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Table 3.1.3.2 : Average formant frequency values of the Kokborok Vowels recorded in isolation, in words and connected speech, produced by 15 men, 15 women and 10 children together with the negative values of formant frequencies. Averages are based on total number of tokens. The formant frequency measurements are in Hertz (Hz). (For isolated vowels, numbers of speakers are 5 men, 3 women and 2 children).

Vowels In Isolation Vowel → /i/ /e/ /a/ /ə/ /ɯ/ /ɔ/ /o/ /u/

M 253 479 609 466 281 563 451 248 f1 W 317 535 660 544 326 636 532 311 C 434 643 776 658 478 724 606 432

M 2356 207 8 1779 1537 1255 865 780 623

f2 W 2498 2224 1883 1688 1345 1008 905 851 C 2645 2362 2008 1821 1507 1156 1093 1035

M 3005 2707 2407 2567 2487 2509 2322 2471

f W 3122 2758 2523 2685 2586 2689 2467 2565 3 C 3295 2899 2690 2845 2776 2792 2676 2683

Negative value M -253 -479 -609 -466 -281 -563 -451 -248 Mns f 1 W -317 -535 -660 -544 -326 -636 -532 -311 C -434 -643 -776 -658 -478 -724 -606 -432

M -2103 -1600 -1170 -1071 -974 -302 -329 -376

Mns (f 2-f1) W -2181 -1689 -1223 -1144 -1019 -372 -373 -540 C -2211 -1719 -1232 -1163 -1029 -432 -487 -603

Table 3.1.3.2 (a) Average formant frequency values and the negative formant frequency values of the Kokborok vowels in isolation.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Vowels In Words Utterance → /mil/ /mel /mal/ /m əla/ /m ɯlɯk/ /m ɔhl/ /mol/ /muluk/ Vowel → /i/ /e/ /a/ /ə/ /ɯ/ /ɔ/ /o/ /u/

M 301 516 632 512 329 625 517 315 f1 W 349 572 685 559 376 658 573 356 C 405 674 765 666 482 764 652 446

M 2243 2085 1660 1469 1128 871 784 608 f2 W 2456 2309 1872 1679 1343 1087 998 819 C 2674 2397 2070 1767 1452 1187 1068 911

M 3103 2730 2448 2597 2475 2597 2327 2418 f3 W 3203 2854 2587 2654 2555 2672 2494 2543 C 3293 2935 2654 2765 2633 2788 2627 2635 Negative value M -301 -516 -632 -512 -329 -625 -517 -315

Mns f 1 W -349 -572 -685 -559 -376 -658 -573 -356 C -405 -674 -765 -666 -482 -764 -652 -446

M -1942 -1569 -1028 -957 -799 -246 -267 -293

Mns (f 2-f1) W -2107 -1737 -1187 -1120 -967 -429 -425 -463 C -2269 -1723 -1305 -1101 -970 -423 -416 -465 Table 3.1.3.2 (b) : Average formant frequency values and the negative formant frequency values of the Kokborok vowels in words.

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Vowels In Connected Speech

Utterance → / b ɔ belai biɡra / / ani m əmla kɯrɯi / / b ɔnɔ sadi jotɔnɔ kubui / Vowel → /i/ /e/ /a/ /ə/ /ɯ/ /ɔ/ /o/ /u/

M 325 534 630 523 341 604 502 320 f1 W 377 582 692 570 391 667 560 376 C 449 665 784 679 507 763 659 450

M 2294 2109 1655 1469 1200 887 798 610

f2 W 2502 2374 1860 1679 1395 1101 1005 901 C 2701 2531 2052 1827 1557 1233 1108 1002

M 3102 2815 2431 2588 2410 2364 2244 2322 f3 W 3222 2945 2671 2732 2508 2683 2487 2574 C 3437 3191 2957 2919 2776 2832 2876 2691 Negative value M -325 -534 -630 -523 -341 -604 -502 -320 Mns f 1 W -377 -582 -692 -570 -391 -667 -560 -377 C -449 -665 -784 -679 -507 -763 -659 -450

M -1969 -1575 -1025 -946 -859 -283 -296 -290

Mns (f 2-f1) W -2125 -1792 -1168 -1109 -1004 -434 -445 -524 C -2252 -1866 -1268 -1148 -1050 -470 -449 -552

Table 3.1.3.2 (c) : Average formant frequency values and the negative formant frequency values of the Kokborok vowels in connected speech.

The average values of f 1, f 2, and f 3 – as given in the above Table 3.1.3.2 (a), (b) and (c) are represented graphically in Figure 3.1.3.2 (a), (b), (c) and (d). In the following figures the vertical axis shows the frequency in Hz and the horizontal axis lists the vowels along with their average formant frequency values. The overall pattern of all these average formant frequency positioning is very similar in the following Figures 3.1.3.2 (a), (b), (c) and (d).

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (a) : Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by men in isolation (black lines), in words (red lines) and connected speech (green lines).

Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (b) : Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by women in isolation (black lines), in words (red lines) and connected speech (green lines).

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Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (c) : Average formant frequency values of the first three formants and the positioning of the Kokborok vowels produced by children in isolation (black lines), in words (red lines) and connected speech (green lines).

However, in all these figures the f 2 frequency goes downwards throughout the series {/i, e, a, ə, ɯ, ɔ, o, u/}. The f 1 frequency goes up for the first three vowels {/i, e, a /}, and then down for the vowels {/ə, ɯ /} and again goes up for the vowel {/ɔ/} and then downwards for the last two vowels {/o, u/}. Similarly, the f3 frequency goes downwards for the vowels {/i, e, a /}. But the f 3 frequency of the vowels {/ə, ɔ, u/} goes up and that of {/ɯ, o/} goes down except that of the vowel {/o/} in connected speech articulated by children. In connected speech of children, the vowel {/o/} goes up.

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Chapter 3: Acoustic Analysis of the Kokborok Vowels

Further, these figures show that the Kokborok front vowels have high f 2 but back vowels have low f 2. The f 1 and f 2 are far apart in front vowels but f 2 and f 3 are close together. The f 1 and f 2 are close together in back vowels but f 2 and f 3 are far apart. For the Kokborok central vowels, formants are almost at equidistance.

Figure 3.1.3.2 (d) : Average formant frequency values of the first three formants and the positioning of the Kokborok vowels in words produced by men (black lines), women (red lines) and children (green lines).

The result of our data analysis given in Table 3.1.3.2 (a), (b) and (c) shows that the average formant frequency values of f 1 for all the vowels produced in isolation by men, women and children is lower than those when the same vowel produced in words and connected speech except the vowels {/i, a/} 102

Chapter 3: Acoustic Analysis of the Kokborok Vowels

in the case of children. In the case of children, the vowels {/i, a/} show low f 1 frequency values when they are produced in words. As for the average formant frequency values of f 2 and f 3 for men, women and children when the vowels are produced in isolation, in words and connected speech, the differences in all the figures are in such a way that no significant generalization seem to be possible. Though these overall patterns are looking alike in all the figures, the actual average formant frequency values do differ in the tables and figures as well. The men have the lowest average formant frequency values; the women have higher average formant frequency values and the children have the highest average formant frequency values as shown in Figure 3.1.3.2 (d) . The negative values given in the Table 3.1.3.2 (a), (b) and (c) are summed from the average f 1 and f 2 values by using the formula (i) {Mns f 1 or

(–f1)} and (ii) [Mns (f 2–f1) or {–(f 2–f1)}] in order to draw the acoustic formant chart. The negative values for all the vowels in Table 3.1.3.2 (a), (b) and (c) are plotted in Figures 3.1.3.2 (e), (f), (g) and (h) for a comparison between the vowels produced in isolation, in words and connected speech by men, women and children. The f 1 frequency for all the vowels is plotted on the vertical axis with the frequency of f 2 on the horizontal axis.

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Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (e) : Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by men in isolation (black line), in words (red line) and connected speech (green line).

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Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (f) : Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by women in isolation (black line) in words (red line) and connected speech (green line).

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Chapter 3: Acoustic Analysis of the Kokborok Vowels

Figure 3.1.3.2 (g) : Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels produced by children in isolation (black line), in words (red line) and connected speech (green line).

The overall patterns are looking alike in all the acoustic vowel diagrams 3.1.3.2 (e), (f) and (g). The black lines in the figures connect the vowels produced in isolation; the red lines connect the vowels produced in words and green lines connect the vowels produced in connected speech. A general observation can be made in the case of men and women. That is, all the vowels when produced in isolation maintain relatively higher ‘vowel height’. But when these vowels are produced in words and connected speech by men and women they show some variation in ‘vowel height’. All the vowels produced in words by men show higher ‘vowel height’ than in connected

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Chapter 3: Acoustic Analysis of the Kokborok Vowels speech except the {/ɔ, o/}. The vowel {/ɔ, o/} show higher ‘vowel height’ in connected speech than vowels in words. But in the case of women, all the vowels in words show higher ‘vowel height’ except the vowel /o/. Only the vowel /o/ shows higher ‘vowel height’ in connected speech.

In other words, the f 1 frequency of each vowel produced in isolation by men and women is lower than that when it is produced in words and connected speech. All the vowels produced in words by men show lower f 1 than the one produced in connected speech except {/ɔ, o/}. The vowels

{/ɔ, o/} show lower f 1 in connected speech compared to the same vowels produced in words. But in case of women, all the vowels in words show lower f1 except the vowel /o/. Only the vowel /o/ shows lower f 1 in connected speech.

The f 2 frequency of each vowel produced by men in isolation remains higher than the one that is produced in words and connected speech. Excepting the vowels {/e, ɔ, o/}, the f 2 frequencies for {/i, a, ə, ɯ, u/} remain relatively higher in isolation than in words and connected speech than the ones when they are produced by women. In case of children there are variations and as such any generalization of the differences seems to be difficult either for the ‘vowel height’ or for the ‘vowel formant frequency’.

Our data analysis in the Table 3.1.3.2 (b) and the following Figure 3.1.3.2 (h) shows that the ‘vowel height’ is higher when the vowels are produced by men in words compared to the vowels produced by women and children. It also shows that the women’s ‘vowel height’ is higher than that of children. However, the f 1 frequency of each vowel produced by men is lower than that of women and children. The f 1 frequency of women, however, is lower than children. The f 2 frequency of each vowel produced by men in a word is lower than that of women and children. Excepting the vowels

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{/e, ə, ɔ, o /}, the f 2 frequency of each vowel produced by women is higher than that of children.

Figure 3.1.3.2 (h) : Acoustic vowel diagram showing average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok vowels in words produced by men (bold dot), women (rectangular) and children (triangular).

Thus, the acoustical measurement of average formant frequency values shown in the Table 3.1.3.2 (a), (b) and (c) and the Figures 3.1.3.2 (e), (f), (g) and (h) and also a careful analysis of the of the first three formants of all the vowels in Kokborok lead us to make the following generalizations:

• The ‘vowel height’ of each of the vowels produced by men in isolation or in words or connected speech is higher than that of women and children.

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The ‘vowel height’ of each of the vowels produced by women in isolation, in words or connected speech is higher than that of children • In Kokborok {/i/ and /e/} are front vowels. But the vowel /e/ is less fronted than /i/. • The central vowels in the language are {/a/, and /ə/}. But the vowels /a/ is less central compared to / ə/. • In Kokborok {/ɔ/, /o/ and /u/} are back vowels. But the vowels /ɔ/ and /o/ are more back than /u/. • The vowel /ɯ/ in fact is a close back unrounded vowel in cardinal vowel chart. But in Kokborok it is slightly centralized.

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Part II: Diphthongs and Triphthong

3.2.1 Results and discussion The results of the diphthongs and triphthong are stated and discussed under the relevant headings which are as follows:

3.2.1.1 Duration measurement of the Kokborok Diphthongs and Triphthong As established earlier in section 2.1.2 that Kokborok has four (4) diphthongs – {/ai , ɔi, au , ua /} and a triphthong – {/uai /}. Here the duration measurements of the Kokborok diphthongs and triphthong are done in milliseconds. The results of a detailed spectrographic study on the average duration values of diphthongs and triphthong in Kokborok are given in the Table 3.2.1.1 . The words used for duration measurement of diphthongs and triphthong are – {/b ai h/, /b ɔih/, /b au ti/, /k ua k/ and / čhuai kɔl/}. The table shows average duration values (in ms) of the onset, transition and offset of the Kokborok diphthongs and triphthong together with the total values produced by 15 men 15 women and 10 children.

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Table 3.2.1.1 : Average duration values of the Kokborok diphthongs and triphthong recorded in words, produced by 15 men, 15 women and 10 children. Averages are based on total number of tokens. The duration measurements are in milliseconds.

Diphthongs In Words Word → /b ai h/ /b ɔih/ Duration of 371 382 Word → Diphthong → /ai/ /ɔi/ Onset Transi Offset Onset Transit Offset Duration → Total ɔ Total a tion i ion i M 48 25 54 127 52 25 47 124 W 82 42 87 211 75 37 69 181 C 58 29 65 152 59 30 50 139

Word → /b au ti/ /k ua k/ Duration of 476 389 Word → Diphthong → /au/ /ua/ Onset Transi Offset Onset Transit Offset Duration → Total Total a tion u u ion a M 51 30 56 137 55 34 51 140 W 87 46 91 224 94 45 87 226 C 63 37 67 167 69 38 62 169 Triphthong In Word h Word → /č uai kɔl/ Duration of 754 Word → Triphthong /uai/ Onset Mid Offset Duration → Transition Transition Total u a i M 53 26 47 27 49 202 W 83 40 65 41 80 309 C 65 33 52 34 60 244 Table 3.2.1.1 : Average duration values of the Kokborok diphthongs and triphthong.

The average duration values of these diphthongs and triphthong as recorded in words produced by men, women and children and as given in the above table are plotted in Figure 3.2.1.1 .

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Figure 3.2.1.1 : Average duration values of the Kokborok diphthongs and triphthong in words produced by men (Blue Colum), women (Red Colum) and children (Green Colum).

The figure presents a comparison amongst the men, women and children and their average duration values. The Table 3.2.1.1 and the Figure 3.2.1.1 show that the Kokborok diphthongs and triphthong in words produced by men have lowest duration, children have the higher duration and women have the highest duration values. It may also be noted from the data given in the Table 3.2.1.1 and the Figure 3.2.1.1 that the duration values of the Kokborok diphthongs produced in words by men, women and children increases in the following order: {ɔi < ai < au < ua}.

3.2.1.2 Formant frequency measurement of the Kokborok Diphthongs Acoustically, ‘a diphthong is a vowel of changing resonance’ (Lawrence J. Raphael et al, 2007). The results of a detailed spectrographic study on the average formant frequency values of diphthongs in Kokborok are given in the Table 3.2.1.2 . This table shows average formant frequency values (in Hz) of the onglide

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(starting) and offglide (final) position of the Kokborok diphthongs produced by 15 men 15 women and 10 children together with the negative values of average formant frequency. Focus here is on the average formant frequency of Kokborok diphthongs recorded in words. Same words are used for formant frequency measurement of diphthongs, which are given in section 3.2.1.1 .

Table 3.2.1.2 Average formant frequency values of the onglide and offglide of the Kokborok diphthongs recorded in words produced by 15 men, 15 women and 10 children together with the negative values of average formant frequencies. Averages are based on total number of tokens. The formant frequency measurements are in Hz.

Diphthong In Words Utterance → /baih/ /b ɔih/ /bauti/ /kuak/ /ai/ /ɔi/ /au/ /ua/ Diphthong Onglide Offglide Onglide Offglide Onglide Offglide Onglide Offglide → /a/ /i/ /ɔ/ /i/ /a/ /u/ /u/ /a/ M 654 320 566 332 651 370 379 646 f1 W 761 411 654 415 755 439 437 762 C 802 519 724 522 799 493 502 797

M 1423 2128 981 2136 1509 821 829 1432 f2 W 1592 2332 1032 2344 1616 968 972 1589 C 1676 2516 1187 2521 1661 1103 1110 1678 Negative value M -654 -320 -566 -332 -651 -370 -379 -646

Mns f W -761 -411 -654 -415 -755 -439 -437 -762 1 C -802 -519 -724 -522 -799 -493 -502 -797

M -769 -1808 -415 -1804 -858 -451 -450 -786

Mns (f -f ) W -831 -1921 -378 -1929 -861 -529 -535 -827 2 1 C -874 -1997 -463 -1999 -862 -610 -608 -881 Table 3.2.1.2 : Average formant frequency values of the onglide and offglide of the Kokborok diphthongs, together with the negative values of average formant frequencies.

The negative values given in the Table 3.2.1.2 are summed up from the average formant frequency values f 1 and f 2 by using the formula (i) {Mns f 1 or

(–f1)} and (ii) [Mns (f 2–f1) or {–(f 2–f1)}] respectively to draw the acoustic formant chart. The negative values of the onglide (starting) and offglide (ending) of Kokborok diphthongs are given in Table 3.2.1.2 plotted in Figures 3.2.1.2 (a), (b)

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Chapter 3: Acoustic Analysis of the Kokborok Vowels and (c) for a comparison of gliding in these diphthongs in words produced by men, women and children. In Figures 3.2.1.2 (a), (b) and (c) the f 1 frequency for all the diphthongs is plotted on the vertical axis with the frequency of f 2 on the horizontal axis.

Figure 3.2.1.2 (a) : Acoustic diagram showing the positioning of average formant frequency values of the onglide and offglide of the Kokborok diphthongs in respect of men .

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Figure 3.2.1.2 (b) : Acoustic diagram showing the positioning of average formant frequency values of the onglide and offglide of the Kokborok diphthongs in respect of women .

Figure 3.2.1.2 (c) : Acoustic diagram showing the positioning of average formant frequency values of the onglide and offglide of the Kokborok diphthongs in respect of children .

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The negative values of each diphthong is plotted in the in Figures 3.2.1.2 (a), (b) and (c) against the four bold dots in the position of the vowels {/i, a, ɔ, u/}. The negative values in the Table 3.2.1.2 show some changing of Hz in the formant frequency of Kokborok diphthongs. The arrowhead indicates the gliding of diphthongs. The acoustic measurement of average formant frequency values of the onglide and offglide of the Kokborok diphthongs is displayed in the Table 3.2.1.2 and the Figures 3.2.1.2 (a), (b) and (c). The analysis of the first tow formants of the vowels {/i, a, ɔ, u/} in Kokborok lead to the following observation:

• The ‘height’ of each of the onglide and offglide of the Kokborok diphthongs produced by men is higher than that of women and children. The ‘height’ of each of the onglide and offglide of the Kokborok diphthongs produced by women is higher than that of children. • The Kokborok diphthongs {/ai/ , / au /} are sharing common onglide, because the formant frequency of the onglide of these two diphthongs i.e. of / a/ is approximately same. The offglide of these two diphthongs are in two different directions i.e. towards /i/ and /u/ respectively because of the differences in formant frequency. These two diphthongs may be termed as wide diphthongs because the distance between onglide and offglide is wider. • The Kokborok diphthongs {/ɔi/, /ai/ } show common offglide, because the formant frequency of the offglide of these two diphthongs i.e. of / i/ is approximately same but the onglide of these two diphthongs differ. This is because of the differences in formant frequency of the onglide i.e. of /ɔ/ and /a/ . These two diphthongs may be termed as wide diphthongs because the distance between onglide and offglide is wider. • The formant frequency of the onglide of the diphthongs /ua/ and and the formant frequency of offglide of the diphthongs /au/ is approximately the

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same. On the other hand, the formant frequency of the offglide of the diphthongs /ua/ and the formant frequency of onglide of the diphthongs /au/ is approximately the same. So, directions of the onglide and offglide of these two diphthongs are contrary to each other.

3.2.1.3 Formant frequency measurement of the Kokborok Triphthong Just as in the case of diphthongs, we have attempted here to analyse the Kokborok ‘triphthong’ acoustically. ‘Triphthong is a single vocalic nucleus which begins with one vowel quality, moves to a second quality, then finishes with a third quality’ (Trask, 1996). The results of a detailed spectrographic study on the average formant frequency values of the triphthong are given in the Table 3.2.1.3 . This table shows average formant frequency values (in Hz) of the onglide (starting) nuclei (mid) and offglide (final) position of the triphthong produced by 15 men, 15 women and 10 children together with the negative values of average formant frequencies. Focus here is on the average formant frequency of the Kokborok triphthong recorded in a word. The same word is used for formant frequency measurement of the triphthong, which is given in section 3.2.1.1 .

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Table 3.2.1.3 : Average formant frequency values of the onglide, nuclei and offglide of the Kokborok triphthong recorded in a word produced by 15 men, 15 women and 10 children together with the negative values of average formant frequencies. Averages are based on total number of tokens. The formant frequency measurements are in Hz.

Triphthong In a Word

→ čh ɔ Utterance / uaik l/ /uai/ Triphthong → Onglide Mid Offglide /u/ /a/ /i/ M 313 62 4 305 f1 W 451 715 403 503 790 517 C

M 823 1502 2113 f2 W 97 8 16 70 24 10 C 1134 1782 2561 Negative value M -313 -624 -305 Mns f W -451 -715 -403 1 C -503 -790 -517

M -510 -878 -1808 Mns (f -f ) W -527 -955 -2007 2 1 C -631 -992 -2044

Table 3.2.1.3 : Average formant frequency values of the onglide, mid and offglide of the Kokborok triphthong, together with the negative values of average formant frequencies.

The negative values given in the above table may be summed from the average formant frequency values of f 1 and f 2 by using the formula (i) {Mns f 1 or (–f1)} and (ii) [Mns (f 2–f1) or {–(f 2–f1)}] respectively to draw the acoustic formant chart. The negative values of the onglide, mid and offglide of the Kokborok triphthong are given in Table 3.2.1.3 and plotted in Figure 3.2.1.3 .

The figure shows the f 1 frequency on the vertical axis and the f 2 frequency on the horizontal axis.

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Figure 3.2.1.3 : Acoustic diagram showing the positioning of average formant frequency values of the onglide, mid and offglide of the Kokborok triphthong in respect of men , women and children .

The negative values of the onglide, mid and offglide of the Kokborok triphthong is plotted in the above Figure 3.2.1.3 against the three bold dots indicating the positions of the vowels {/u, a, i/}. The negative values in the Table 3.2.1.3 show some changing of Hz in the formant frequency for men, women and children. The arrowhead indicates the gliding of triphthong. The 119

Chapter 3: Acoustic Analysis of the Kokborok Vowels acoustic measurement of average formant frequency values of the onglide, mid and offglide of the Kokborok triphthong displayed in the Table 3.2.1.3 and the Figure 3.2.1.3 and also the analysis of the first two formants of the vowels {/u, a, i/} in Kokborok lead to the following observations:

• The ‘height’ of the onglide, mid and offglide of the Kokborok triphthong produced by men is more than that of women and children. The ‘height’ of onglide, mid and offglide of Kokborok triphthong produced by women is more than that of children. • The onglide, mid and offglide of the Kokborok triphthong /uai/ differ from each other in terms of Hz. The formant frequency of the onglide, mid and offglide of this triphthong i.e. of /uai/ moves in different directions i.e. /u/ moves towards /a/ , and /a/ moves towards /i/ because of the changes in formant frequency of every element in triphthong.

• The average values of f 1 and f 2 of onglide, nuclei and offglide of the triphthong /uai/ are at such a distance that they create a triangular. The mapping in the above Figure 3.2.1.3 displayed the onglide, mid and offglide of the triphthong /uai/ . These are positioned in three different corners of the triangular. So, the vowels {u, a, and i} in the triphthong /uai/ can be considered as corner vowels. This is in agreement with Maddieson (1984) who considered them as corner vowels. In cardinal vowel chart, these vowels are located in three different corners.

3.2.2 Findings On the basis of the acoustic measurements and the analysis of the first three formants of all the vowels, four diphthongs and a triphthong in Kokborok, we find the following:

1. The duration of all the Kokborok vowels whether produced in isolation or in words or connected speech by men, women or children differ

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Chapter 3: Acoustic Analysis of the Kokborok Vowels from one another on the basis of speaker and his or her gender and age group. We also find that sounds articulated in connected speech take the shortest duration, sounds articulated in words take longer duration and sounds articulated in isolation take the longest duration.

2. The duration measurements of the Kokborok vowels support the findings of investigators of American English vowels (e.g. James Hillenbrand, Laura A. Getty, Michael J. Clark and Kimberlee Wheeler, 1994 and 1995). The variations of vowels in terms of their speakers come up in such a way that men have the shortest duration; children have longer duration and women have the longest duration.

3. Our analysis also confirms the view that the Kokborok low vowel has longer duration than the high vowels.

4. It is noted that the duration of percentage of Kokborok vowels produced in words by men, women and children increases in the following order: Men → { ə < ɯ < u < ɔ < a < o < e < i }, Women → { ə < ɯ < u < ɔ < o < e < a < i } and Children → { ɯ < ə < u < ɔ < e < o < a < i }.

5. All the vowels in Kokborok whether produced in isolation, in words or connected speech vary from one another on the basis of their formant frequencies.

6. It is noted that the Kokborok front vowels have high f 2 but back vowels have low f 2. Further f 1 and f 2 are far apart in front vowels but f 2 and f 3 are close together. The f 1 and f 2 are close together in back vowels but f 2 and f 3 are far apart. It is also noted that for central vowel, f 1, f2 and f 3 frequencies are at equidistance.

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7. The acoustic measurements of the Kokborok vowels also confirms that the ‘vowel height’ in respect of children is the lowest; for women it is higher and for men, the highest when the vowels are produced in isolation, in words or connected speech.

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Chapter 4 : Acoustic Analysis of the Kokborok Consonants ______

4.0 Overview The present chapter presents the acoustic analysis of the Kokborok consonant. For the convenience of the study this chapter is divided into two parts. Part one deals with the acoustic analysis of the Kokborok obstruents and part two deals with the acoustic analysis of the Kokborok sonorants. Both the parts of this chapter give a numerical analysis of the Kokborok obstruents as well as sonorants. Further the chapter gives both individual variation and gender variation of frequency and duration. The chapter ends with the findings of overall acoustic analysis of the Kokborok consonants.

Part I: Obstruents

4.1.1 Introduction For acoustic analysis of a speech segment, the LPC based signal processing and Broad or wide band spectrographic analysis are used. For this study the broad band analysis is felt to be convenient as this type of analysis is very helpful for the analysis of segmental phonemes. This study concentrates on the measurement of formant frequencies. The formants appear horizontally starting at the bottom of the spectrograms and are called formant one (f 1), formant two (f 2) and formant three (f 3) etc and are measured in Hertz (Hz).

4.1.2 Method The method includes a description of participants, stimuli and procedure used to study the Kokborok consonants acoustically.

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4.1.2.1 Participants In this study in total forty (40) Kokborok speakers participated. They include fifteen (15) men, fifteen (15) women and ten (10) twelve to fifteen years old children (5 boys and 5 girls). All of them are native speakers of Kokborok and they belong to Tripura. All of them are multilingual and can speak the Kokborok, Bengali, English, Hindi languages. All of them have received no phonetic training and knowledge of this kind of experiments.

4.1.2.2 Stimuli The stimuli contain forty four (44) tokens of the Kokborok consonants in monosyllabic words, in polysyllabic words and in connected speech.

4.1.2.3 Procedure For the acoustic analysis of the Kokborok consonant phonemes, audio recording of men, women and children were made. The recordings of nineteenth (19) consonant phonemes of Kokborok comprise several readings of each target word on a digital audio recorder. The speech analysis software ‘Praat’ is used to generate and draw waveforms as well as spectrograms. The middle part of each of the recordings is used for the acoustic analysis. The consonant phonemes of Kokborok are studied within the parameter of duration, voice onset time (VOT), formant frequency and formant transition as well. The entire speech of informants is transcribed and presented in the form of broad transcription using International Phonetics Alphabet. For the actual acoustic measurements of consonant phonemes numbers are used comprehensively. The mean value of the numbers of the phonemes is taken and represented graphically.

4.1.3 Results and discussion For systematic presentation of the results of this acoustic study as well as our discussions on these results, the contents of this chapter are divided into

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Chapter 4: Acoustic Analysis of the Kokborok Consonants two parts. In the first part we discuss the obstruents in Kokborok; in the second, we focus on its sonorants. The results are stated and discussed under the relevant headings which are as follows:

4.1.3.1 Closure Duration measurement of the Kokborok Stops The closure duration of stop is known the acoustic interval corresponding to the articulatory occlusion (Kent and Read 1995). In this section the closure duration measurements of all Kokborok voiceless, voiced and aspirated stops are done in milliseconds. The results of waveform and a detailed spectrographic study on the average closure duration values of voiceless, voiced and aspirated stops in Kokborok are given in the Table 4.1.3.1 (a), (b) and (c). Here focus is on the closure duration of Kokborok voiceless, voiced and aspirated stops recorded in monosyllabic words, in polysyllabic words and in connected speech. The utterances used for duration measurement are {/pa/, /ta/, /ka/, /p ha/, /t ha/, /čha/, /k ha/, /ba/, /da/, /ǰa/, /ɡa/}, {/apa/, /ata/, /akar/, /ap ha/, /at haŋ/, /ka čha/, /ak hata/, /haba/, /hada/, /ra ǰa/, /aɡar/} and {(i) /puk hur kinar ɔ ta ačhukdi/ (ii) /apha t haihc huk čhahk ha/ and (iii) /b ɔ san ǰao n ɔɡɔ tɔŋdi/}. The table shows the average closure duration values (in ms) of Kokborok voiceless and voiced stops, produced by 15 men 15 women and 10 twelve to fifteen years old children together with the average duration of overall utterance and percentage of closure duration within the overall utterance.

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Table 4.1.3.1 : Average closure duration and VOT (release burst + aspiration) values of the Kokborok Stops recorded in monosyllabic words, polysyllabic words and connected speech, produced by 15 men 15 women and 10 children, together with the duration of overall utterance and percentage of closure duration and VOT within the overall utterance. Averages are based on total number of tokens. The closure duration and VOT measurements are in milliseconds.

Stops in Monosyllabic words Voiceless Stops Voiceless aspirated Stops Voiced Stops Utterance → /pa/ /ta/ /ka/ /p ha/ /t ha/ /čha/ /k ha/ /ba/ /da/ /ǰa/ /ɡa/ Phoneme → /p/ /t/ /k/ /p h/ /t h/ /čh/ /k h/ /b/ /d/ /ǰ/ /ɡ/ Duration M 223 215 212 375 369 341 325 291 259 252 242 of overall W 343 329 321 448 432 422 416 389 376 343 337 utterance C 247 231 219 399 383 363 350 298 289 271 266

M Closure 127 119 105 117 112 109 101 97 95 93 89 W 178 166 147 169 143 127 119 138 132 125 123 duration C 138 135 123 124 123 115 111 109 107 105 97

% of Closure M 56.95 55.35 49.53 31.20 30.35 31.96 31.08 33.33 36.68 36.90 37.78 duration W 51.90 50.46 45.79 37.72 33.10 30.09 28.61 35.48 35.11 36.44 36.50 within the overall C 55.87 58.44 56.16 31.08 32.11 31.68 31.71 36.58 37.02 38.75 36.47 utterance

Duration M 24 26 28 11 12 14 19 34 36 37 39 of Release W 21 25 27 9 11 12 16 32 34 36 37 Burst C 18 20 24 8 9 11 11 29 31 33 36

Duration M …… …… …… 22 23 24 25 …… …… …… …… of W …… …… …… 17 18 19 21 …… …… …… …… Aspiration C …… …… …… 13 14 16 17 …… …… …… ……

M 24 26 28 33 35 38 44 -34 -36 -37 -39 VOT W 21 25 27 26 29 31 37 -32 -34 -36 -37 C 18 20 24 21 23 27 28 -29 -31 -33 -36

% of VOT M 10.76 12.09 13.21 8.80 9.49 11.14 13.54 -11.68 -13.90 -14.68 -16.12 within the W 6.12 7.60 8.41 5.80 6.71 7.35 8.89 -8.23 -9.04 -10.50 -10.98 overall C 7.29 8.66 10.95 5.26 6.00 7.44 8.00 -9.73 -10.73 -12.18 -13.53 utterance Table 4.1.3.1 (a) : Average closure duration and VOT values of the Kokborok Stops in monosyllabic words and the duration of overall utterance and the percentage of closure duration and VOT within the overall utterance.

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Stops in Polysyllabic words Voiceless Stops Voiceless aspirated Stops Voiced Stops Utterance → /apa/ /ata/ /akar/ /ap ha/ /at haŋ/ /ka čha/ /ak hata/ /haba/ /hada/ /ra ǰa/ /aɡar/ Phoneme → /p/ /t/ /k/ /p h/ /t h/ /čh/ /k h/ /b/ /d/ /ǰ/ /ɡ/ Duration M 410 415 492 471 559 556 598 473 479 481 493 of overall W 503 505 545 522 641 637 627 521 523 513 537 utterance C 460 452 504 483 579 571 567 489 488 498 516

M Closure 124 117 103 112 96 94 92 89 83 71 68 W 141 138 135 133 125 121 114 115 109 105 101 duration C 127 119 118 115 109 105 103 99 92 87 71

% of Closure M 30.24 28.19 20.93 23.78 17.17 16.91 15.38 18.82 17.33 14.76 13.79 duration within the W 28.03 27.33 24.77 25.48 19.50 18.99 18.18 22.07 20.84 20.47 18.81 overall utterance C 27.61 26.33 23.41 23.81 18.83 18.39 19.05 20.25 20.54 17.47 13.76

Duration M 11 14 15 8 10 13 17 19 24 25 28 of Release W 10 11 13 7 7 11 13 17 21 23 26 Burst C 8 9 12 5 6 9 11 15 16 18 22

Duration M …… …… …… 17 18 20 21 …… …… …… …… of W …… …… …… 14 15 18 19 …… …… …… …… Aspiration C …… …… …… 10 12 13 16 …… …… …… ……

M 11 14 15 25 28 33 38 -19 -24 -25 -28 VOT W 10 11 13 21 22 29 32 -17 -21 -23 -26 C 8 9 12 15 18 22 27 -15 -16 -18 -22

% of VOT M 2.68 3.37 3.05 5.31 5.01 5.94 6.35 -4.02 -5.01 -5.20 -5.68 within the W 1.99 2.18 2.39 4.02 3.43 4.55 5.10 -3.26 -4.02 -4.48 -4.84 overall C 1.74 1.99 2.38 3.11 3.11 3.85 4.76 -3.06 -3.28 -3.61 -4.26 utterance Table 4.1.3.1 (b) : Average closure duration and VOT values of the Kokborok stops in polysyllabic words and the duration of overall utterance and the percentage of closure duration and VOT within the overall utterance.

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Stops in Connected Speech Voiceless Stops Voiceless aspirated Stops Voiced Stops Utterance → /p uk hur kinar ɔ ta /a pha thaihc huk čhah kha/ /b ɔ san ǰao n ɔɡɔ tɔŋdi/ ačhukdi/ Phoneme → /p/ /t/ /k/ /p h/ /t h/ /čh/ /k h/ /b/ /d/ /ǰ/ /ɡ/ Duration M 1602 1612 1790 of overall W 2453 2746 2561 utterance C 1799 1697 1951

M Closure 99 95 87 93 89 82 79 75 69 65 57 W 122 119 117 115 113 111 109 107 105 103 98 duration C 102 97 89 95 92 85 83 79 73 71 68

% of Closure M 6.18 5.93 5.43 5.77 5.52 5.09 4.90 4.19 3.85 3.63 3.18 duration within the W 4.97 4.84 4.77 4.19 4.12 4.04 3.97 4.18 4.10 4.02 3.83 overall utterance C 5.67 5.39 4.95 5.60 5.42 5.01 4.89 4.05 3.74 3.64 3.49

Duration M 11 14 16 9 10 12 13 17 22 23 24 of Release W 9 11 13 7 9 11 12 15 18 21 22 Burst C 7 8 10 5 6 8 9 12 13 15 19

Duration M …… …… …… 12 15 14 16 …… …… …… …… of W …… …… …… 11 13 13 15 …… …… …… …… Aspiration C …… …… …… 9 10 12 14 …… …… …… ……

M 11 14 16 21 25 26 29 -17 -22 -23 -24 VOT W 9 11 13 18 22 24 27 -15 -18 -21 -22 C 7 8 10 14 16 20 23 -12 -13 -15 -19

% of VOT M 0.69 0.87 0.99 1.30 1.55 1.61 1.80 -0.95 -1.23 -1.28 -1.34 within the W 0.37 0.45 0.53 0.66 0.80 0.87 0.98 -0.59 -0.70 -0.82 -0.86 overall C 0.39 0.44 0.56 0.82 0.94 1.18 1.36 -0.62 -0.67 -0.78 -0.97 utterance Table 4.1.3.1 (c) : Average closure duration and VOT values of the Kokborok stops in connected speech and the duration of overall utterance and the percentage of closure duration and VOT within the overall utterance.

The average closure duration values of the Kokborok stops – as given in the above Table 4.1.3.1 (a), (b) and (c) are represented graphically in Figure 4.1.3.1 (a), (b), (c) and (d). In these following figures the vertical axis shows the time duration in millisecond and the horizontal axis lists the stops along with their

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Chapter 4: Acoustic Analysis of the Kokborok Consonants average closure duration values. The overall patterns of all these average closure duration values is very similar in the following Figures. The closure duration of the Kokborok stops are discussed here in terms of manner of articulation, voicing quality and place of articulation.

Figures 4.1.3.1 (a): Average closure duration values of the Kokborok stops produced by men in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

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Figures 4.1.3.1 (b): Average closure duration values of the Kokborok stops produced by women in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

Figures 4.1.3.1 (c): Average closure duration values of the Kokborok stops produced by children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

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The Table 4.1.3.1 (a), (b) and (c) and the Figure 4.1.3.1 (a), (b), (c) show that stops in monosyllabic words produced by men, women and children have longer closure durations than when they are produced in polysyllabic words and in connected speech. Our data analysis and observation found that the movement of the articulator is slow in monosyllabic words but the movement of the articulator is fast in polysyllabic words and in connected speech. This is in agreement with the claim made by Hardcastle (1973) i.e. ‘the faster the movement of the articulator is, the shorter the closure duration’. In terms of place of articulation, these tables and figures show the labial stops take the longest closure duration, the coronal stops take shorter closure duration, the dorso-palatal stops take next shorter closure duration and the dorso-velar stops take the shortest closure duration in monosyllabic words and polysyllabic words and also in connected speech produced by men, women or children. This is in agreement with Maddieson (1991) i.e. ‘closure duration of a stop reduces with the backness of the tongue’. The hierarchy (in terms of place of articulation) of the closure duration of the Kokborok stops is → labial > coronal > dorso-palatal > dorsal dorso-velar. The hierarchy of the closure duration of labial, coronal, dorso-palatal and dorso-velar stops is given in the following: Voiceless unaspirated stops → { p> t > k } Voiceless aspirated stops → { ph > t h > čh> kh } and Voiced stops → { b > d > ǰ > ɡ }.

In terms of voice quality, these tables and figures show that voiceless stops take longer closure duration in comparison to their voiced counterpart. This is in agreement with the claim made by Ladefoged (2002) that ‘voiceless consonants are longer than voiced consonants’. The hierarchy of the closure duration of voiceless and voiced stops is given in the following: { p > b }, { t > d }, { ǰ } and { k > ɡ}.

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In terms of aspiration and unaspiration, these tables and figures show that unaspirated stops have longer closure duration than their aspirated counterpart. The hierarchy of the closure duration of aspirated and unaspirated stops is given in the following: { p > p h }, { t > t h }, {čh} and { k > kh}.

Figures 4.1.3.1 (d): Average closure duration values of the Kokborok stops in polysyllabic words, produced by men (Red Colum), women (Green Colum) and children (Blue Colum).

Moreover the Table 4.1.3.1 (b) and the Figure 4.1.3.1 (d) exhibit that stops in polysyllabic words produced by men have the shortest closure duration, children have longer closure durations and women have the longest closure durations. The percentage of closure duration within the overall utterance is shown in the Table 4.1.3.1 (a), (b) and (c). These tables show that the percentage of closure duration in monosyllabic words, in polysyllabic words and in connected speech

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Chapter 4: Acoustic Analysis of the Kokborok Consonants produced by men, women or children is varied in such a way that any significant generalization seems to be difficult.

Figure 4.1.3.1 (e) : Percentage of closure duration within the overall utterance produced by men in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

But the Table 4.1.3.1 (a), (b) and (c) and the Figure 4.1.3.1 (e) can lead to some common generalizations. That is, (i) the percentage of closure duration in a monosyllabic word is more, in a polysyllabic word it is less and in connected speech, the least. (ii) The percentage of closure duration of voiceless unaspirated sounds is more than their respective voiced counterparts.

4.1.3.2 Voice Onset Time (VOT) measurement of the Kokborok Stops The VOT measurements of all the Kokborok stops are done in milliseconds. The results of waveform and a detailed spectrographic study show that voiced stops { /b/, /d/, /ǰ/, /ɡ/ } are negative because the pitch contours were preceding the release burst. The results of data analysis on the average VOT values of voiceless, voiced and aspirated stops in Kokborok are given in the Table 4.1.3.1 (a), (b) and (c). Here focus is on the VOT values of Kokborok voiceless, 135

Chapter 4: Acoustic Analysis of the Kokborok Consonants voiced and aspirated stops recorded in monosyllabic words, polysyllabic words and in connected speech. The Table 4.1.3.1 (a), (b) and (c) show average positive and negative VOT values (in ms) of Kokborok stops, produced by 15 men 15 women and 10 children together with the average duration of overall utterance and percentage of VOT values within the overall utterance.

The average VOT values of the Kokborok stops – as given in the above Table 4.1.3.1 (a), (b) and (c) are demonstrated graphically in Figure 4.1.3.2 (a), (b), (c) and (d). In the following figures the vertical axis show the time duration in milliseconds and the horizontal axis lists the stops along with their average VOT values. The overall pattern of all these average VOT movement is very similar in the following Figures. The VOT of the Kokborok stops are discussed here in terms of manner of articulation, voicing quality and place of articulation.

Figures 4.1.3.2 (a): Average VOT values of the Kokborok stops produced by men in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

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Figures 4.1.3.2 (b): Average VOT values of the Kokborok stops produced by women in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

Figures 4.1.3.2 (c): Average VOT values of the Kokborok stops produced by children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum). 137

Chapter 4: Acoustic Analysis of the Kokborok Consonants

Kokborok has three-way contrast series of stops namely voiceless, voiced and aspirated. Voiceless unaspirated stops { p, t, k} and voiceless aspirated stops {ph, t h, čh, kh} have positive VOT. Voiced stops {b, d, ǰ, ɡ} have negative VOT. The Table 4.1.3.1 (a), (b) and (c) and the Figure 4.1.3.2 (a), (b) and (c) show that the VOT duration of stops in monosyllabic words is longer, in

polysyllabic words it is shorter and in connected speech, the shortest. In terms of place of articulation, these tables and figures show that the labial stops have the shortest VOT, the coronal stops have long VOT, the dorso-palatal stops have longer VOT and the dorso-velar stops have the longest VOT in monosyllabic words, polysyllabic words and even in connected speech produced by men, women or children. This is in agreement with Fischer-Jørgensen (1954), Peterson and Lehiste (1960) i.e. ‘further the back the place of articulation is, the longer the VOT’. But it is in disagreement with Hardcastle’s (1973) view i.e. ‘the faster the movement of the articulator is, the shorter the VOT’. The hierarchy of the VOT of the Kokborok stops are → labial < coronal < dorso-palatal < dorso-velar. The hierarchy of the VOT of labial, coronal, dorso-palatal and dorso-velar stops is given in the following: Voiceless unaspirated stops → { p< t < k } Voiceless aspirated stops → { ph < t h < čh < kh} and Voiced stops → { -b< -d < -ǰ < -ɡ}. Here this study also shows that the degree of VOT difference is there. In terms of aspiration and unaspiration these tables and figures show that the voiceless unaspirated stop has shorter VOT than the voiceless aspirated stop. The hierarchy of the VOT of unaspirated and aspirated stops is as follows: { p< p h }, {t < t h}, {čh}, {k < k h}.

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In terms of voice quality, these tables and figures show that the voiceless unaspirated stop has shorter VOT than the voiced unaspirated stop. The hierarchy of the VOT of voiceless unaspirated and voiced unaspirated stops is as follows: { p< -b}, {t < -d }, { -ǰ } and { k < -ɡ}.

Figures 4.1.3.2 (d): Average VOT values of the Kokborok stops in polysyllabic words, produced by men (Red Colum), women (Green Colum) and children (Blue Colum).

The Table 4.1.3.1 (a), (b) and (c) and the Figure 4.1.3.2 (d) show that the VOT for men is longer, for women it is shorter and for children, the shortest. It is because the movement of the articulator of children is faster than that of men and women and the movement of the articulator of women is faster than that of men. Our data analysis and observation is supporting the result found by Hardcastle (1973) i.e. ‘the faster the movement of the articulator is, the shorter the VOT’. However, the percentage of VOT within the overall utterances is also shown in the Table 4.1.3.1 (a), (b) and (c). These tables show that the percentage of VOT in monosyllabic words, in polysyllabic words and in connected speech

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produced either by men, women or children is varied in such a way that any significant generalization seems to be difficult.

Figure 4.1.3.2 (e) : Percentage of VOT within the overall utterances produced by men in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

It may be noted that the Table 4.1.3.1 (a), (b) and (c) and the Figure 4.1.3.2 (e) can lead to some overall generalizations. These are (i) the percentage of VOT in a monosyllabic word is more, in a polysyllabic word less and in connected speech is the least. (ii) The percentage of VOT of anterior sounds is less in comparison to posterior sounds. And (iii) the percentage of VOT of voiceless unaspirated sounds is less than their voiced counterparts. It may also be noted that the relationship between closure duration and VOT is inversely proportional i.e. the closure duration decreases as the VOT increases and vice versa. The hierarchy of the inversely proportional relationship between closure duration and VOT is given in the following:

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Closure duration of unaspirated stops { p> t > k } and VOT { p< t < k } h h h h h h h h Closure duration of aspirated stops {p >t > č > k } and VOT {p < t < č d > ǰ > ɡ} and VOT {-b< -d < -ǰ < -ɡ}.

The difference between closure duration and VOT is shown together in Figure 4.1.3.2 (f).

Figure 4.1.3.2 (f): Average closure duration + VOT values of Kokborok stops in polysyllabic words, produced by men , women and children .

The data analysis shows that Kokborok stops are in agreement with the claim made by Lehiste (1960) that ‘characteristically VOT increase with the backness of the stop’s place of articulation’. The study also agrees with the finding of Maddieson (1997) that ‘the closure duration for bilabial stops is, in general,

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Chapter 4: Acoustic Analysis of the Kokborok Consonants longer than that of alveolar and velar, possibly due to different degree of air pressure in the cavity behind the constriction’.

4.1.3.3 Formant transition measurement of the last glottal pulse leading to the Kokborok Voiceless stops

In this section, the formant transition measurements of the last glottal pulse leading to the Kokborok voiceless unaspirated and aspirated stops are done in Hertz. The results of the detailed spectrographic study on the average formant transition of the last glottal pulse of voiceless stops in Kokborok are given in the Table 4.1.3.3 . Here focus is on the formant transition of the last glottal pulse leading to the Kokborok labial, coronal, dorso-palatal and dorso-velar voiceless stops recorded in words. The utterances used for transition measurement are {/apa/, /ata/, /akar/} and {/ap ha/, /at haŋ/, /ka čha/, /ak hata/}. The table shows the average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops (in Hz), produced by 15 men, 15 women and 10 twelve to fifteen years old children.

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Table 4.1.3.3 : Average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops recorded in words, produced by 15 men, 15 women and 10 children. Averages are based on total number of tokens. The formant transition measurements are in Hertz.

Voiceless un aspirated Stops

Utterance → /apa/ /ata/ /akar/

Phoneme → /p/ /t/ /k/

M 854 710 785

f transition W 971 900 93 6 1

C 1052 10 20 961

M 256 2 19 40 145 6 f2 transition W 267 4 229 5 1533 C 277 5 236 3 1534 M 3249 310 3 314 3 f3 transition W 3311 321 1 3206 C 3621 350 7 34 70 Voiceless aspirated Stops h h h h Utterance → /ap a/ /at aŋ/ /ka č a/ /ak ata/ h h h h Phoneme → /p / /t / /č / /k / M 717 602 67 4 61 8 f1 transition W 799 704 764 696 C 894 811 80 2 788 M 245 4 1818 1537 1124 f2 transition W 2483 2252 180 4 1363 C 2572 211 4 182 2 1415

M 3164 2292 348 5 3370 f transition W 358 3 246 8 3517 34 90 3 C 36 80 259 4 3607 3689 Table 4.1.3.3 : Average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops.

The average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops – as given in the above Table 4.1.3.3 are represented graphically in Figure 4.1.3.3 . In the following figure the vertical axis shows the formant transition in Hz and the horizontal axis lists the Kokborok voiceless stops.

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Figure 4.1.3.3 : The diagram showing average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops (in Hz) of f 1 (blue line), f2 (red line) and f 3 (green line) in a word produced by men , women and children .

The representation of the average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops in the above diagram shows that the last glottal pulse for men is lower, for women it is higher and for children, the highest. The above diagram also shows that the average formant transition values of the last glottal pulse leading to the Kokborok voiceless stops is higher in unaspirated voiceless stops than the voiceless aspirated stops.

The analysis presented in the Table 4.1.3.3 shows that the average formant transition range of the last glottal pulse leading to the Kokborok voiceless stops (in Hertz) in case of each of the voiceless stop when produced by men, women or children in words are different from each other. The formant transition of the last glottal pulse leading to the Kokborok voiceless stops is discussed below:

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Labial stop /p/ :

• The average f1 transition of the last glottal pulse leading to /p/ produced by men , women and children in a word is 854 Hz, 971 Hz and 1052 Hz

respectively. The average f2 transition of the last glottal pulse leading to /p/ produced by men , women and children in a word is 2562 Hz,

2674 Hz and 2775 Hz respectively. The average f3 transition of the last glottal pulse leading to /p/ produced by men , women and children in a word is 3249 Hz, 3311 Hz and 3621 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /p/ is ranging between 854 Hz – 3621 Hz.

Labial stop /p h/: h • The average f1 transition of the last glottal pulse leading to /p / produced by men , women and children in a word is 717 Hz, 799 Hz and 894 Hz

respectively. The average f2 transition of the last glottal pulse leading to /p h/ produced by men , women and children in a word is 2454 Hz,

2483 Hz and 2572 Hz respectively. The average f3 transition of the last glottal pulse leading to /p h/ produced by men , women and children in a word is 3164 Hz, 3583 Hz and 3680 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /p h/ is ranging between 717 Hz - 3680 Hz.

Coronal stop /t/ :

• The average f1 transition of the last glottal pulse leading to /t/ produced by men , women and children in a word is 710 Hz, 900 Hz and 1020 Hz

respectively. The average f2 transition of the last glottal pulse leading to /t/ produced by men , women and children in a word is 1940 Hz, 2295 Hz

and 2363 Hz respectively. The average f3 transition of the last glottal

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pulse leading to /t/ produced by men , women and children in a word is 3103 Hz, 3211 Hz and 3507 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /t/ is ranging between 710 Hz – 3507 Hz.

Coronal stop /t h/: h • The average f1 transition of the last glottal pulse leading to /t / produced by men , women and children in a word is 602 Hz, 704 Hz and 811 Hz

respectively. The average f2 transition of the last glottal pulse leading to /t h/ produced by men , women and children in a word is 1818 Hz,

2252 Hz and 2114 Hz respectively. The average f3 transition of the last glottal pulse leading to /t h/ produced by men , women and children in a word is 2292 Hz, 2468 Hz and 2594 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /t h/ is ranging between 602 Hz – 2594 Hz.

Dorso-palatal stop /čh/:

h • The average f1 transition of the last glottal pulse leading to /č / produced by men , women and children in a word is 674 Hz, 764 Hz and 802 Hz

respectively. The average f2 transition of the last glottal pulse leading to /čh/ produced by men , women and children in a word is 1537 Hz,

1804 Hz and 1822 Hz respectively. The average f3 transition of the last glottal pulse leading to /čh/ produced by men , women and children in a word is 3485 Hz, 3517 Hz and 3607 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /čh/ is ranging between 674 Hz - 3607 Hz.

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Dorso-velar stop /k/ :

• The average f1 transition of the last glottal pulse leading to /k/ produced by men , women and children in a word is 785 Hz, 936 Hz and 961 Hz

respectively. The average f2 transition of the last glottal pulse leading to /k/ produced by men , women and children in a word is 1456 Hz,

1533 Hz and 1534 Hz respectively. The average f3 transition of the last glottal pulse leading to /k/ produced by men , women and children in a word is 3143 Hz, 3206 Hz and 3470 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /k/ is ranging between 785 Hz – 3470 Hz.

Dorso-velar stop /k h/: h • The average f1 transition of the last glottal pulse leading to /k / produced by men , women and children in a word is 618 Hz, 696 Hz and 788 Hz

respectively. The average f2 transition of the last glottal pulse leading to /k h/ produced by men , women and children in a word is 1124 Hz,

1363 Hz and 1415 Hz respectively. The average f3 transition of the last glottal pulse leading to /k h/ produced by men , women and children in a word is 3370 Hz, 3490 Hz and 3689 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /k h/ is ranging between 618 Hz – 3689 Hz.

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4.1.3.4 Formant frequency measurement of the Kokborok voiced Stops In this section, the formant frequency measurements of all the Kokborok voiced stops are done in Hertz (Hz). The results of the detailed spectrographic study on the average formant frequency values of voiced stops in Kokborok are given in the Table 4.1.3.4. Here focus is on the formant frequency of Kokborok labial, coronal, dorso-palatal and dorso-velar voiced stops recorded in monosyllabic words, in polysyllabic words and in connected speech. The utterances used for formant frequency measurement are {/ba/, /da/, /ǰa/, /ɡa/}, {/haba/, /hada/, /ra ǰa/, /aɡar/} and {(i) /b ɔ san ǰao n ɔɡɔ tɔŋdi/}. The table shows the average formant frequency values (in Hz) of the Kokborok voiced stops, produced by 15 men, 15 women and 10 twelve to fifteen years old children.

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Table 4.1.3.4: Average formant frequency values of the Kokborok voiced stops recorded in monosyllabic words, polysyllabic words and in connected speech, produced by 15 men, 15 women and 10 children. Averages are based on total number of tokens. The formant frequency measurements are in Hertz (Hz).

Voiced Stops

In Monosyllabic words Utterance → /ba/ /da/ /ǰa/ /ɡa/ Phoneme → /b/ /d/ /ǰ/ /ɡ/ M 476 446 416 401 f1 W 54 3 50 2 531 502 C 67 4 60 5 66 9 61 3 M 211 5 15 90 1248 81 7 f2 W 2235 164 3 137 6 102 1 C 231 5 1695 1537 1093 M 2793 201 6 2245 1777

f3 W 2876 252 6 2513 1976 C 3455 2788 2597 2239 In Polysyllabic words

Utterance → /haba/ /hada/ /ra ǰa/ /aɡar/ Phoneme → /b/ /d/ /ǰ/ /ɡ/ M 533 502 540 525

f1 W 667 62 7 623 61 2 C 786 748 80 8 73 1 M 2235 1717 1318 905 f2 W 2369 1961 1607 1178 C 2455 1958 1722 1332

M 308 9 2282 254 4 197 7 f3 W 3204 2985 2680 2370 C 3735 3354 2970 3180 In Connected Speech Utterance → /b ɔ san ǰao n ɔɡɔ tɔŋdi/ Phoneme → /b/ /d/ /ǰ/ /ɡ/ M 549 522 560 549 f1 W 685 633 653 618 C 907 817 87 8 750

M 2357 180 6 1413 970 f2 W 240 9 1986 168 8 1292 C 2614 2264 2022 1644 M 3175 2323 2644 2102 f3 W 35 80 3018 27 60 2745 C 3914 3764 3070 375 1

Table 4.1.3.4: Average formant frequency values of the Kokborok voiced stops.

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The average values of f 1 and f 2 – as given in the above Table 4.1.3.4 are represented graphically in Figure 4.1.3.4. In the following figure the vertical axis shows the f 1 in Hz and the horizontal axis shows the f 2 in Hz.

Figure 4.1.3.4: The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok voiced stops produced in polysyllabic words by men (black dot), women (red rectangle) and children (green triangle).

The representation of the frequency values of f 1 and f 2 in the above diagram shows that the Kokborok voiced stops such as /b/ is towards the front part of the diagram, /d/ is in the mid part of the diagram, / ǰ/ is towards the backwards in the diagram and / ɡ/ is towards the back part of the diagram. The representation of the Kokborok voiced stops in the above diagram corresponds to the vocal tract. That is, in the vocal tract /b/ is labial, /d/ is coronal, / ǰ/ is dorso-palatal and / ɡ/ is dorso-velar.

Further, the analysis presented in the Table 4.1.3.4 shows that the average formant frequency range (in Hertz) in vocal tract in case of each of the Kokborok voiced stops when produced by men, women or children either in monosyllabic words, polysyllabic words or in connected speech are

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Chapter 4: Acoustic Analysis of the Kokborok Consonants different from each other. The formant frequency is discussed below for each voiced stop:

Labial stop /b/ :

• The average f 1 of /b/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 476 Hz, 533 Hz and 549 Hz

respectively. The average f 1 of /b/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

543 Hz, 667 Hz and 685 Hz respectively. The average f 1 of /b/ produced by children in a monosyllabic word, polysyllabic word and in connected

speech is 674 Hz, 786 Hz and 907 Hz respectively. The average f 1 of Kokborok /b/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 476 Hz – 907 Hz.

• The average f 2 of /b/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 2115 Hz, 2235 Hz and

2357 Hz respectively. The average f 2 of /b/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

2235 Hz, 2369 Hz and 2409 Hz respectively. The average f 2 of /b/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 2315 Hz, 2455 Hz and 2614 Hz respectively. The

average f 2 of Kokborok /b/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 2115 Hz – 2614 Hz.

• The average f3 of /b/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 2793 Hz, 3089 Hz and

3175 Hz respectively. The average f 3 of /b/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

2876 Hz, 3204 Hz and 3580 Hz respectively. The average f 3 of /b/

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produced by children in a monosyllabic word, polysyllabic word and in connected speech is 3455 Hz, 3735 Hz and 3914 Hz respectively. The

average f 3 of Kokborok /b/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 2793 Hz - 3914 Hz.

• The f 1, f2 and f 3 of Kokborok /b/ is ranging between 476 Hz – 3914 Hz.

Coronal Stop /d/ :

• The average f 1 of /d/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 446 Hz, 502 Hz and 522 Hz

respectively. The average f 1 of /d/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

502 Hz, 627 Hz and 633 Hz respectively. The average f 1 of /d/ produced by children in a monosyllabic word, polysyllabic word and in connected

speech is 605 Hz, 748 Hz and 817 Hz respectively. The average f 1 of Kokborok /d/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 446 Hz – 817 Hz.

• The average f 2 of /d/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 1590 Hz, 1717 Hz and

1806 Hz respectively. The average f 2 of /d/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

1643 Hz, 1961 Hz and 1986 Hz respectively. The average f 2 of /d/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 1695 Hz, 1958 Hz and 2264 Hz respectively. The

average f 2 of Kokborok /d/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 1590 Hz – 2264 Hz.

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• The average f 3 of /d/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 2016 Hz, 2282 Hz and

2323 Hz respectively. The average f 3 of /d/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

2526 Hz, 2985 Hz and 3018 Hz respectively. The average f 3 of /d/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 2788 Hz, 3354 Hz and 3764 Hz respectively. The

average f 3 of Kokborok /d/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 2016 Hz – 3764 Hz.

• The f1, f2 and f3 of Kokborok /d/ is ranging between 446 Hz – 3764 Hz.

Dorso-palatal Stop / ǰ/:

• The average f 1 of /ǰ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 416 Hz, 540 Hz and 560 Hz

respectively. The average f 1 of /ǰ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is 531 Hz, 623 Hz

and 653 Hz respectively. The average f 1 of /ǰ/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is

669 Hz, 808 Hz and 878 Hz respectively. The average f 1 of Kokborok /ǰ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 416 Hz – 878 Hz.

• The average f 2 of /ǰ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 1248 Hz, 1318 Hz and

1413 Hz respectively. The average f 2 of /ǰ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

1376 Hz, 1607 Hz and 1688 Hz respectively. The average f 2 of /ǰ/ produced by children in a monosyllabic word, polysyllabic word and in

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connected speech is 1537 Hz, 1722 Hz and 2022 Hz respectively. The

average f 2 of Kokborok /ǰ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 1248 Hz – 2022 Hz.

• The average f3 of /ǰ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 2245 Hz, 2544 Hz and

2644 Hz respectively. The average f 3 of /ǰ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

2513 Hz, 2680 Hz and 2760 Hz respectively. The average f 3 of /ǰ/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 2597 Hz, 2970 Hz and 3070 Hz respectively. The

average f 3 of Kokborok /ǰ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 2245 Hz – 3070 Hz.

• The f1, f2 and f3 of Kokborok /ǰ/ is ranging between 416 Hz – 3070 Hz.

Dorso-velar Stop / ɡ/:

• The average f 1 of /ɡ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 401 Hz, 525 Hz and 549 Hz

respectively. The average f 1 of /ɡ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

502 Hz, 612 Hz and 618 Hz respectively. The average f 1 of /ɡ/ produced by children in a monosyllabic word, polysyllabic word and in connected

speech is 613 Hz, 731 Hz and 750 Hz respectively. The average f 1 of Kokborok /ɡ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 401 Hz – 750 Hz.

• The average f 2 of /ɡ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 817 Hz, 905 Hz and 970 Hz

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respectively. The average f 2 of /ɡ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

1021 Hz, 1178 Hz and 1292 Hz respectively. The average f 2 of /ɡ/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 1093 Hz, 1332 Hz and 1644 Hz respectively. The

average f 2 of Kokborok /ɡ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 817 Hz – 1644 Hz.

• The average f 3 of /ɡ/ produced by men in a monosyllabic word, polysyllabic word and in connected speech is 1777 Hz, 1977 Hz and

2102 Hz respectively. The average f 3 of /ɡ/ produced by women in a monosyllabic word, polysyllabic word and in connected speech is

1976 Hz, 2370 Hz and 2745 Hz respectively. The average f 3 of /ɡ/ produced by children in a monosyllabic word, polysyllabic word and in connected speech is 2239 Hz, 3180 Hz and 3751 Hz respectively. The

average f 3 of Kokborok /ɡ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or in connected speech is ranging between 1777 Hz – 3751 Hz.

• The f1, f2 and f3 of Kokborok /ɡ/ is ranging between 401 Hz – 3751 Hz.

4.1.3.5 Noise duration or frication duration measurement of the Kokborok Fricatives The noise duration or frication duration of fricatives is basically based on air turbulence produced by various kinds of constriction in the vocal tract. Here, the noise duration measurements of all the Kokborok fricatives are done in milliseconds. The results of waveform and a detailed spectrographic study on the average noise duration values of fricatives in Kokborok are given in the Table 4.1.3.5. The focus here is on the noise duration of the Kokborok fricatives recorded in monosyllabic words, polysyllabic words and in connected speech. The utterances

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Chapter 4: Acoustic Analysis of the Kokborok Consonants used for noise duration measurement are {/sa/, /ha/}, {/kasa/, /kaham/} and {(i) /b ɔnɔ sadi ani həmbai/}. The table shows average noise duration values (in ms) of the Kokborok fricatives, produced by 15 men, 15 women and 10 children, together with the average duration of overall utterance and percentage of noise duration within the overall utterance.

Table 4.1.3.5: Average noise duration or frication duration values of the Kokborok Fricatives recorded in monosyllabic words, polysyllabic words and connected speech, produced by 15 men, 15 women and 10 children, together with the duration of overall utterance and percentage of noise duration in the overall utterance. Averages are based on the total number of tokens. The noise duration measurements are in milliseconds.

Table 4.1.3.5: Average frication duration and percentage of frication values of the Kokborok Fricatives.

The average noise duration values of the Kokborok fricatives – as given in the above Table 4.1.3.5 are represented graphically in Figure 4.1.3.5 (a) . In the following figure the vertical axis shows the time duration in millisecond and the horizontal axis lists the fricatives along with their average noise duration values. The noise duration of the Kokborok fricatives are discussed here in terms of manner of articulation and place of articulation.

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Figures 4.1.3.5 (a) : Average noise duration values of the Kokborok fricatives produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

The Table 4.1.3.5 and the Figure 4.1.3.5 (a) show the fricatives produced by men, women and children in monosyllabic words, polysyllabic words and connected speech. The noise duration of the fricatives in a monosyllabic word is the longest, in a polysyllabic word it is shorter, and in connected speech, the shortest. Our data analysis and observation found that the fricatives produced by women have longest noise duration, children have shorter noise duration and men have the shortest noise duration. In terms of place of articulation, the table and figure show that coronal fricative /s/ takes longer noise duration than glottal fricative /h/ either in monosyllabic words, polysyllabic words or in connected speech produced by either men, women or children. The hierarchy, in terms of place of articulation, of the noise duration of the Kokborok fricatives is → coronal > glottal. The hierarchy of the noise duration or frication duration of coronal and glottal fricatives is → {s > h }.

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The percentage of noise duration within the overall utterances is also displayed in the Table 4.1.3.5. It is represented graphically in Figure 4.1.3.5 (b) below. The table and figure show that the percentage of noise duration in monosyllabic words, polysyllabic words and in connected speech produced either by men, women or children is varied in such a way that any significant generalization does not seem to be possible.

Figure 4.1.3.5 (b) : Percentage of noise duration in the overall utterances produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

But the Table 4.1.3.5 and the Figure 4.1.3.5 (b) can lead to some common generalizations that, (i) the percentage of noise duration in a monosyllabic word is more, in a polysyllabic word is less and in connected speech is the least. (ii) The percentage of noise duration of / s/ is more in comparison to / h/. But in case of men and children the coronal fricative / s/ shows less percentage of noise duration than the glottal fricative / h/ only in monosyllabic words.

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4.1.3.6 Formant transition measurement of the last glottal pulse leading to the Kokborok Fricatives

In this section, the formant transition measurements of the last glottal pulse leading to the Kokborok fricatives are done in Hertz. The results of the detailed spectrographic study on the average formant transition of the last glottal pulse of fricatives in Kokborok are given in the Table 4.1.3.6. Here focus is on the formant transition of the last glottal pulse leading to the Kokborok coronal and glottal fricatives recorded in words. The utterances used for transition measurement are {/kasa/, /kaham/}. The table shows the average formant transition values of the last glottal pulse leading to the Kokborok fricatives (in Hz), produced by 15 men, 15 women and 10 twelve to fifteen years old children.

Table 4.1.3.6: Average formant transition values of the last glottal pulse leading to the Kokborok fricatives recorded in words, produced by 15 men, 15 women and 10 children. Averages are based on total number of tokens. The formant transition measurements are in Hertz.

Fricatives Utterance → /kasa/ /kaham/ Phoneme → /s/ /h/ M 1421 909 f1 transition W 1509 1003 C 178 4 124 7 M 330 2 1343 f2 transition W 3407 1502 C 3480 1709

M 32 40 162 6 f3 transition W 3420 1936 C 3506 2002 Table 4.1.3.6: Average formant transition values of the last glottal pulse leading to the Kokborok fricatives.

The average formant transition values of the last glottal pulse leading to the Kokborok fricatives – as given in the above Table 4.1.3.6 are represented graphically in Figure 4.1.3.6. In the following figure the vertical axis shows the formant transition in Hz and the horizontal axis lists the Kokborok fricatives.

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Figure 4.1.3.6: The diagram showing average formant transition values of the last glottal pulse leading to the Kokborok fricatives (in Hz) of f 1 (blue line), f 2 (red line) and f 3 (green line) in a word produced by men , women and children .

The representation of the average formant transition values of the last glottal pulse leading to the Kokborok fricatives in the above diagram shows that the last glottal pulse for men is lower, for women it is higher and for children, the highest. The above diagram also shows that the average formant transition values of the last glottal pulse leading to the Kokborok fricatives is higher in coronal fricative /s/ than the glottal fricative /h/ .

Our data analysis presented in the Table 4.1.3.6 shows that the average formant transition range of the last glottal pulse leading to the Kokborok fricatives (in Hertz) in case of each of the fricatives when produced by men, women or children in words are different from each other. The formant transition of the last glottal pulse leading to the Kokborok fricatives is discussed below:

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Coronal fricative /s/ :

• The average f1 transition of the last glottal pulse leading to /s/ produced by men , women and children in a word is 1421 Hz, 1509 Hz and

1784 Hz respectively. The average f2 transition of the last glottal pulse leading to /s/ produced by men , women and children in a word is

3302 Hz, 3407 Hz and 3480 Hz respectively. The average f3 transition of the last glottal pulse leading to /s/ produced by men , women and children in a word is 3240 Hz, 3420 Hz and 3506 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /s/ is ranging between 1421 Hz – 3506 Hz.

Glottal fricative /h/ :

• The average f1 transition of the last glottal pulse leading to /h/ produced by men , women and children in a word is 909 Hz, 1003 Hz and 1247 Hz

respectively. The average f2 transition of the last glottal pulse leading to /h/ produced by men , women and children in a word is 1343 Hz,

1502 Hz and 1709 Hz respectively. The average f3 transition of the last glottal pulse leading to /h/ produced by men , women and children in a word is 1626 Hz, 1936 Hz and 2002 Hz respectively.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /h/ is ranging between 909 Hz – 2002 Hz.

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Part II: Sonorants

4.2.1 Results and discussion The Kokborok sonorants and their acoustic feature are discussed under the relevant headings which are as follows:

4.2.1.1 Closure or murmur Duration measurement of the Kokborok Nasals The duration of nasal sounds are measured with the articulatory features of the closure of the oral cavity and the opening of the nasal cavity. In this section the closure or murmur duration measurements of all the Kokborok nasals are done in milliseconds. The results of waveform and a detailed spectrographic study on the average closure duration values of nasals in Kokborok are given in the Table 4.2.1.1 . Here focus is on the closure duration of the Kokborok nasals recorded in monosyllabic words, polysyllabic words and in connected speech. The utterances used for duration measurement are { /ham/, /han/, /ha ŋ/ }, { /lama/, /lana/, /la ŋa/ } and {(i) /nini mu ŋ tamɔ/ }. The table shows average closure duration values (in ms) of the Kokborok nasals, produced by 15 men, 15 women and 10 children, together with the average duration of overall utterances and percentage of nasal murmur duration within the overall utterance.

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Table 4.2.1.1 : Average murmur duration values of the Kokborok Nasals recorded in monosyllabic words, polysyllabic words and connected speech, produced by 15 men, 15 women and 10 children, together with the duration of overall utterances and percentage of closure duration within the overall utterance. Averages are based on total number of tokens. The closure duration measurements are in milliseconds. Nasals Nasals in Nasals in Polysyllabic Nasals in

Monosyllabic words words Connected Speech Utterance → /ha m/ /ha n/ /ha ŋ/ /la ma/ /la na/ /la ŋa/ /ni ni muŋ tamɔ/? Phoneme → m n ŋ m n ŋ m n ŋ Duration M 352 331 327 467 452 433 1392 of overall W 483 471 458 503 498 487 2107 utterance C 397 378 356 483 465 451 1901

M 85 76 67 74 65 61 58 55 53 Duration of Nasals W 107 101 94 98 95 87 87 83 77 C 89 81 72 79 71 67 69 67 62

% of Closure M 24.15 22.96 20.50 15.85 14.38 14.09 4.17 3.95 3.81 duration within the W 22.15 21.44 20.52 19.48 19.08 17.86 4.13 3.94 3.65 overall utterance C 22.42 21.43 20.22 16.36 15.27 14.86 3.63 3.52 3.26

Table 4.2.1.1 : Average closure or murmur duration values of the Kokborok Nasals.

The average closure duration values of the Kokborok nasals – as given in the above Table 4.2.1.1 are represented graphically in Figure 4.2.1.1 (a). In the following figure the vertical axis shows the time duration in millisecond and the horizontal axis lists the nasals along with their average closure duration values. The overall pattern of all these average closure duration values is very similar in the following Figure. The closure duration of the Kokborok nasals is discussed here in terms of place of articulation.

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Figures 4.2.1.1 (a) : Average closure or murmur duration values of the Kokborok Nasals produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

Table 4.2.1.1 and Figure 4.2.1.1 (a) show that nasals in monosyllabic words produced by men, women and children have longer closure durations, in polysyllabic words have shorter closure durations and in connected speech have the shortest closure durations. Our data analysis found that the movement of the articulator is slow in monosyllabic words but it is fast in polysyllabic words and in connected speech. This is in agreement with the claim made by Hardcastle (1973) i.e. “the faster the movement of the articulator is, the shorter the closure duration”. It is also seen that the Kokborok nasals in monosyllabic words, polysyllabic words or in connected speech produced by women have longer duration; children have shorter duration and men have the shortest duration. In terms of place of articulation, the table and the figure show that labial nasal /m/ takes longer closure duration, coronal nasal /n/ takes shorter closure duration and dorso-velar nasal /ŋ/ takes the shortest closure duration, either in monosyllabic words, polysyllabic words or in connected speech produced by men,

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Chapter 4: Acoustic Analysis of the Kokborok Consonants women or children. The hierarchy, in terms of place of articulation, of the closure duration of the Kokborok nasal is → labial > coronal > dorso-velar. The hierarchy of the closure or murmur duration of labial, coronal and dorso-velar nasals is → {m > n > ŋ}. The percentage of closure duration within the overall utterances is also displayed in the Table 4.2.1. 1. They are represented graphically in Figure 4.2.1.1 (b) . The table and figure show that the percentage of closure duration in monosyllabic words, polysyllabic words and in connected speech produced by men, women or children is varied in such a way that any significant generalization seems to be difficult.

Figure 4.2.1.1 (b) : Percentage of closure duration within the overall utterances produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and in connected speech (Blue Colum).

One may draw some common generalizations from Table 4.2.1.1 and the Figure 4.2.1.1 (b) . These are, (i) the percentage of closure duration in monosyllabic words is more, in polysyllabic words it is less and in connected speech it is the

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least. (ii) In case of polysyllabic words, the percentage of closure duration of nasals for women is more, for children it is less and for men the least.

4.2.1.2 Formant frequency measurement of the Kokborok Nasals The nasal consonants are characterized by both formants found in oral cavity and anti-formants associated with nasal cavity. In this section, the formant frequency measurements of all the Kokborok nasals are done in Hertz (Hz). The results of a detailed spectrographic study on the average formant frequency of nasals in Kokborok are given in the Table 4.2.1.2. Here focus is on the formant frequency of Kokborok labial, coronal and dorso-velar nasals recorded in monosyllabic words, polysyllabic words and in connected speech. The same utterances given in section 4.2.1.1 are used for formant frequency measurement. The table shows average formant frequency (in Hz) of the Kokborok nasals produced by 15 men, 15 women and 10 children.

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Table 4.2.1.2 : Average formant frequency values of the Kokborok nasals recorded in monosyllabic words, polysyllabic words and in connected speech, produced by 15 men, 15 women and 10 children. Averages are based on total number of tokens. The formant frequency measurements are in Hertz. Nasals Nasals in Nasals in Polysyllabic Nasals in Connected Utterance Monosyllabic words words Speech → /ha m/ /ha n/ /ha ŋ/ /la ma/ /la na/ /la ŋa/ /ni ni mu ŋ ta mɔ/? Phoneme → m n ŋ m n ŋ m n ŋ Formants M 270 295 331 277 308 343 294 329 363 f1 W 335 350 368 358 379 405 376 399 433 C 348 387 418 368 409 454 397 433 480

M 1803 1681 1491 1847 1623 1468 1882 1703 1479 f2 W 1975 1792 1610 1983 1801 1621 1984 1811 1625 C 1973 1898 1765 1979 1901 1784 1981 1903 1780

M 2086 2203 2303 2323 2483 2418 2344 2447 2623 f 3 W 2175 2252 2391 2452 2618 2569 2624 2665 2778

C 2305 2414 2456 2628 2718 2821 2852 2928 2966 Average formants and anti-formants of Male m n ŋ f1 280 311 346 Anti-formant 392 435 ………

m n ŋ f2 1844 1669 1479 Anti-formant 2582 2337 ………

Table 4.2.1.2 Average formant frequency values of the Kokborok nasals in monosyllabic words, polysyllabic words and in connected speech.

The average values of f1 and f 2 – as given in the Table 4.2.1.2 above are represented graphically in Figure 4.2.1.2 (a), (b), (c) and (d). In the following figures the vertical axis shows the f 1 in Hz and the horizontal axis shows the f 2 in Hz. The overall pattern of all these average formant frequency positioning is very similar in the following Figures 4.2.1.2 (a), (b), (c) and (d).

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Figure 4.2.1.2 (a) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by men in monosyllabic words (black dot), polysyllabic words (red rectangle) and in connected speech (green triangle).

Figure 4.2.1.2 (b) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by women in monosyllabic words (black dot), polysyllabic words (red rectangle) and in connected speech (green triangle).

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Figure 4.2.1.2 (c) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced by children in monosyllabic words (black dot), polysyllabic words (red rectangle) and in connected speech (green triangle).

Figure 4.2.1.2 (d) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok nasals produced in polysyllabic words by men (black dot), women (red rectangle) and children (green triangle).

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The overall patterns are almost similar in all the diagrams 4.2.1.2 (a), (b) (c) and (d). However, a general observation can be made from the above diagrams. That is, average values of f 1 and f 2 show that the all the Kokborok nasal sounds are towards the higher region of the diagram. Kokborok / m/ tends to be represented towards the front part of the diagrams, /n/ tends to be represented in the mid part of the diagrams and /ŋ/ tends to be represented towards the back part of the diagrams when produced by men, women or children either in monosyllabic words, polysyllabic words or in connected speech. The comparison between the representation of average values of f 1 and f 2 of all the Kokborok nasals in all the diagrams with the vocal tract leads to the following generalizations: • The Kokborok / m/ tends to be represented towards the front part of the diagrams and this sound is labial in the vocal tract. • The Kokborok / n/ tends to be represented in the mid part of the diagrams and this sound is coronal in the vocal tract. • The Kokborok /ŋ/ tends to be represented towards the back part of the diagrams and this sound is dorsal in the vocal tract.

Our analysis given in the Table 4.2.1.2 however shows that the average formant frequency range (in Hertz) in oral tract of each of the Kokborok nasals when produced by men, women or children either in monosyllabic words, polysyllabic words or in connected speech is different from each other. The average formant frequency range of each Kokborok nasal is given below:

Labial Nasal /m/ :

• The average f 1 of /m/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 270 Hz, 277 Hz and 294 Hz

respectively. The average f 1 of /m/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 335 Hz, 358 Hz and 376 Hz

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respectively. The average f 1 of /m/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 348 Hz, 368 Hz and 397 Hz

respectively. The average f 1 of Kokborok /m/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 270 Hz – 397 Hz.

• The average f 2 of /m/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1803 Hz, 1847 Hz and 1882 Hz

respectively. The average f 2 of /m/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1975 Hz, 1983 Hz and

1984 Hz respectively. The average f 2 of /m/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 1973 Hz,

1979 Hz and 1981 Hz respectively. The average f 2 of Kokborok /m/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 1803 Hz – 1984 Hz.

• The average f 3 of /m/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2086 Hz, 2323 Hz and 2344 Hz

respectively. The average f 3 of /m/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2175 Hz, 2452 Hz and

2624 Hz respectively. The average f 3 of /m/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 2305 Hz,

2628 Hz and 2852 Hz respectively. The average f3 of Kokborok /m/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2086 Hz – 2852 Hz.

• The f1, f2 and f3 of Kokborok /m/ is ranging between 270 Hz – 2852 Hz.

Coronal Nasal /n/ :

• The average f 1 of /n/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 295 Hz, 308 Hz and 329 Hz respectively. The

average f 1 of /n/ produced by women in a monosyllabic word, polysyllabic

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word and connected speech is 350 Hz, 379 Hz and 399 Hz respectively. The

average f 1 of /n/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 387 Hz, 409 Hz and 433 Hz respectively. The

average f 1 of Kokborok /n/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 295 Hz – 433 Hz.

• The average f 2 of /n/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1681 Hz, 1623 Hz and 1703 Hz respectively.

The average f 2 of /n/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1792 Hz, 1801 Hz and 1811 Hz

respectively. The average f 2 of /n/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 1898 Hz, 1901 Hz and

1903 Hz respectively. The average f 2 of Kokborok /n/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 1623 Hz – 1903 Hz.

• The average f3 of /n/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2203 Hz, 2483 Hz and 2447 Hz respectively.

The average f3 of /n/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2252 Hz, 2618 Hz and 2665 Hz

respectively. The average f3 of /n/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 2414 Hz, 2718 Hz and

2928 Hz respectively. The average f3 of Kokborok /n/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2203 Hz – 2928 Hz.

• The f1, f2 and f3 of Kokborok /n/ is ranging between 295 Hz – 2928 Hz.

Dorso-velar nasal /ŋ/:

• The average f 1 of /ŋ/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 331 Hz, 343 Hz and 363 Hz respectively. The

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average f 1 of /ŋ/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 368 Hz, 405 Hz and 433 Hz respectively. The

average f 1 of /ŋ/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 418 Hz, 454 Hz and 480 Hz respectively. The

average f 1 of Kokborok /ŋ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 331 Hz – 480 Hz.

• The average f 2 of /ŋ/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1491 Hz, 1468 Hz and 1479 Hz respectively.

The average f 2 of /ŋ/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1610 Hz, 1621 Hz and 1625 Hz

respectively. The average f 2 of /ŋ/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 1765 Hz, 1784 Hz and

1780 Hz respectively. The average f 2 of Kokborok /ŋ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 1468 Hz – 1784 Hz.

• The average f 3 of /ŋ/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2303 Hz, 2418 Hz and 2623 Hz respectively.

The average f 3 of /ŋ/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2391 Hz, 2569 Hz and 2778 Hz

respectively. The average f 3 of /ŋ/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 2456 Hz, 2821 Hz and

2966 Hz respectively. The average f 3 of Kokborok /ŋ/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2303 Hz – 2966 Hz.

• The f1, f2 and f3 of Kokborok /ŋ/ is ranging between 331 Hz –2966 Hz.

However, Fujimura (1962) has found that ‘in nasal consonants, there is a high density of formants and the existence of anti-formants. The formant

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Chapter 4: Acoustic Analysis of the Kokborok Consonants frequency measurement of nasal sounds depends on the length of the oral cavity and the measurement of anti-formants of nasal sounds depends on the length of the nasal cavity’. The Table 4.2.1.2 shows the average formant frequencies and anti-formants (in Hz) of the Kokborok nasals of all the utterances produced by male speakers only. The average formant frequency and anti-formant values as given in the Table 4.2.1.2 are represented graphically in Figure 4.2.1.2 (e) . In this figure the vertical axis shows the formant frequency in Hz and the horizontal axis lists the formant frequency and anti-formant values.

Figure 4.2.1.2 (e) : The diagram showing average formant frequency (red Colum) and anti-formant (green Colum) values (in Hz) of f 1 and f 2 of the Kokborok nasals.

The average formant frequency and anti-formant values are given in the

Table 4.2.1.2 and Figure 4.2.1.2 (e) . That is, the average f1 of /m/ , /n/ and /ŋ/ is 280 Hz, 311 Hz and 346 Hz respectively. The anti-formant of f1, which is

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() calculated by using the formula [ F = ], for /m/ is 392 Hz and for /n/ n it is 435 Hz. The average f2 of /m/ , /n/ and /ŋ/ is 1844 Hz, 1669 Hz and 1479

Hz respectively. The anti-formant of f2 (which is also calculated by using the same formula given above), for /m/ is 2582 Hz and for /n/ it is 2337 Hz. The close inspection of the average formant frequency and anti-formant values given in the above table and figure of all the nasals in Kokborok lead to the following observations:

• The anti-formant of f1 in /m/ is lower and in /n/ is higher. The hierarchy

of the anti-formant of f1is → {m < n}.

• The anti-formant of f2 in /m/ is higher and in /n/ is lower. The hierarchy

of the anti-formant of f2 is → {m > n}.

• The sequence between anti-formant of f1 and anti-formant of f2 of the

Kokborok nasals is the reverse one i.e. the anti-formant of f1 increases

from labial < coronal but anti-formant of f2 decreases in the same order such as labial > coronal.

4.2.1.3 Duration measurement of the Kokborok Approximants In this section, the duration measurements of the Kokborok approximants are done in milliseconds. The values of a detailed spectrographic study on the average duration of approximants in Kokborok are given in the Table 4.2.1.3. Here focus is on the duration of the Kokborok approximants recorded in monosyllabic words, polysyllabic words and connected speech. The utterances used for duration measurement are {/la/, /ra/, /ja/}, {/kalam/, /kara/, /aja ŋ/} and {/b ɔhr ɔk hamaja k ɯlai t ɔŋɔ/}. The table shows average duration values (in ms) of the Kokborok approximants, produced by 15 men, 15 women and 10 twelve to fifteen years old children (5 boys and 5 girls), together with the average duration of overall utterance and percentage of approximants duration within the overall utterance.

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Table 4.2.1.3: Average duration values of the Kokborok approximants recorded in monosyllabic words, polysyllabic words and connected speech, produced by 15 men, 15 women and 10 children, together with the duration of overall utterance and percentage of approximants duration within the overall utterance. Averages are based on total number of tokens. The duration measurements are in milliseconds. Approximants Approximants in Approximants in Approximants in Monosyllabic words Polysyllabic words Connected Speech Utterance → /b ɔhr ɔk hamaja k ɯlai /ra/ /la/ /ja/ /kara/ /kalam/ /aja ŋ/ tɔŋɔ/ Phoneme → r l j r l j r l j Duration M 428 396 379 503 485 447 1527 of overall W 476 467 421 579 563 541 2121 utterance C 457 438 402 541 513 501 1873

Duration M 172 107 161 121 82 113 89 55 77 of W 231 163 212 182 131 165 112 91 103 Approxi mants C 205 137 179 159 101 147 104 78 91

% of M 40.19 27.02 42.48 24.06 16.91 25.28 5.83 3.60 5.04 duration within the W 48.53 34.90 50.36 31.43 23.27 30.49 5.28 4.29 4.86 overall utterance C 44.86 31.28 44.53 29.39 19.69 29.34 5.55 4.16 4.86 Table 4.2.1.3 : Average duration values of the Kokborok approximants.

The average duration values of these approximants as recorded in monosyllabic words, polysyllabic words and connected speech, produced by men, women and children as given in the 4.2.1.3 are plotted in Figure 4.2.1.3 (a) . This figure presents a comparison amongst the men, women and children and their average duration values.

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Figure 4.2.1.3 (a) : Average duration values of the Kokborok approximants produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and connected speech (Blue Colum).

The Table 4.2.1.3 and the Figure 4.2.1.3 (a) clearly show that approximants in monosyllabic words produced by men, women or children have longer duration, in polysyllabic words have shorter duration and in connected speech have the shortest duration. Further this Table and the Figure show that the average duration of approximants of children produced in a monosyllabic word, polysyllabic word or connected speech is longer than the men’s duration and shorter than the women’s duration.

In terms of place of articulation, the above table and figure show that alveolar lateral approximant /l/ takes the shortest duration, palatal central approximant /j/ takes longer duration and alveolar central approximant /r/ takes the longest duration in monosyllabic words, polysyllabic words or connected speech, produced by either men, women or children. The hierarchy, in terms of place of articulation, of the duration of the Kokborok approximants is → alveolar lateral approximant < palatal central approximant < alveolar central approximant. The hierarchy of the duration of

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Chapter 4: Acoustic Analysis of the Kokborok Consonants alveolar lateral approximant, palatal central approximant and alveolar central approximant is → {l < j < r }.

However, the percentage of approximants duration within the overall utterance is also displayed in the Table 4.2.1.3. It is represented graphically in Figure 4.2.1.3 (b) . The table and figure show that the percentage of approximants duration in monosyllabic words, polysyllabic words and connected speech produced either by men, women or children is varied in such a way that any significant generalization seems to be difficult.

Figure 4.2.1.3 (b) : Percentage of approximants duration within the overall utterances produced by men, women and children in monosyllabic words (Red Colum), polysyllabic words (Green Colum) and connected speech (Blue Colum).

Table 4.2.1.3 and the Figure 4.2.1.3 (b) also lead to some common generalizations. That is, (i) the percentage of the duration of approximants in a monosyllabic word is more, in a polysyllabic word it is less and in connected speech, the least. (ii) In case of a monosyllabic word, the percentage of duration of approximants for women is more, for children it is less and for men, the least.

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4.2.1.4 Formant frequency measurement of the Kokborok Approximants The Kokborok approximants are characterized by the proximity of the articulator to such an extent that turbulent airstream is produced through the partial closure of the articulators. In this section, the formant frequency measurements of all the Kokborok approximants are done in Hertz (Hz). The results of a detailed spectrographic study on the average formant frequency of approximants are given in the Table 4.2.1.4. Here focus is on the formant frequency of the Kokborok approximants recorded in monosyllabic words, polysyllabic words and connected speech. The same utterances are used for formant frequency measurement, which are given in section 4.2.1.3. The table shows average formant frequency (in Hz) of the Kokborok approximants, produced by 15 men, 15 women and 10 twelve to fifteen years old children.

Table 4.2.1.4: Average formant frequency values of the Kokborok approximants recorded in monosyllabic words, polysyllabic words and connected speech, produced by 15 men, 15 women and 10 twelve to fifteen years old children (5 boys and 5 girls). Averages are based on total number of tokens. The formant frequency measurements are in Hertz. Approximants Approximants in Approximants in Approximants in

Monosyllabic words Polysyllabic words Connected Speech Utterance /b ɔhr ɔk hamaja k ɯlai → /ra/ /la/ /ja/ /kara/ /kalam/ /aja ŋ/ tɔŋɔ/ Phoneme r l j r l j r l j →

M 258 315 298 272 322 329 273 332 309 f1 W 292 345 327 308 366 352 319 358 343 C 338 393 375 358 417 403 354 422 408

M 1545 1537 1273 1602 1578 1304 1492 1620 1308 f2 W 1692 1667 1373 1792 1704 1411 1761 1721 1373 C 1734 1729 1553 1771 1738 1577 1782 1769 1543

M 2066 2426 2316 2103 2567 2506 2234 2506 2290 f 3 W 2302 2663 2516 2301 2737 2661 2363 2702 2493

C 2408 2722 2605 2483 2803 2742 2502 2783 2615

Table 4.2.1.4 Average formant frequency values of the Kokborok approximants in monosyllabic words, polysyllabic words and connected speech.

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The average values of f 1 and f 2 – as given in the above Table are represented graphically in Figure 4.2.1.4 (a), (b), (c) and (d). In the following figures the vertical axis show the f 1 in Hz and the horizontal axis show the f 2 in Hz. The overall pattern of all these average formant frequency positioning is very similar in the following Figures 4.2.1.4 (a), (b), (c) and (d).

Figure 4.2.1.4 (a) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by men in monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle).

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Figure 4.2.1.4 (b) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by women in monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle).

Figure 4.2.1.4 (c) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced by children in monosyllabic words (black dot), polysyllabic words (red rectangle) and connected speech (green triangle).

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Figure 4.2.1.4 (d) : The diagram showing the positioning of average formant frequency values (in Hz) of f 1 and f 2 of the Kokborok approximants produced in polysyllabic words by men (black dot), women (red rectangle) and children (green triangle).

The overall patterns are looking alike in all the diagrams 4.2.1.4 (a), (b) (c) and (d). However, the following general observation can be made about the findings in the above diagrams: The representation of average values of f 1 and f2 show that the Kokborok / r/ , / l/ and /j/ are in the mid part of the diagrams when produced by men, women or children either in monosyllabic words, polysyllabic words or connected speech. The comparison between the representation of average values of f 1 and f 2 of all the Kokborok approximants in all the diagrams with the vocal tract can lead to the generalization that the Kokborok / r/ , / l/ and /j/ are in the mid part of the diagrams and these sounds are alveolar central approximant, alveolar lateral approximant and palatal central approximant respectively. However, the results in the Table 4.2.1.4 show that the average formant frequency range (in Hertz) in oral tract of each Kokborok approximant when produced by men, women or children either in monosyllabic words, polysyllabic words or connected speech is different from

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Alveolar Central Approximant /r/ :

• The average f 1 of /r/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 258 Hz, 272 Hz and 273 Hz

respectively. The average f 1 of /r/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 292 Hz, 308 Hz and

319 Hz respectively. The average f 1 of /r/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 338 Hz,

358 Hz and 354 Hz respectively. The average f 1 of Kokborok /r/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 258 Hz – 358 Hz.

• The average f 2 of /r/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1545 Hz, 1602 Hz and

1492 Hz respectively. The average f 2 of /r/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1692 Hz,

1792 Hz and 1761 Hz respectively. The average f 2 of /r/ produced by children in a monosyllabic word, polysyllabic word and connected

speech is 1734 Hz, 1771 Hz and 1782 Hz respectively. The average f 2 of Kokborok /r/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 1492 Hz – 1792 Hz.

• The average f 3 of /r/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2066 Hz, 2103 Hz and

2234 Hz respectively. The average f 3 of /r/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2302 Hz,

2301 Hz and 2363 Hz respectively. The average f 3 of /r/ produced by

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children in a monosyllabic word, polysyllabic word and connected

speech is 2408 Hz, 2483 Hz and 2502 Hz respectively. The average f 3 of Kokborok /r/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2066 Hz - 2502 Hz.

• The f 1, f 2 and f 3 of Kokborok /r/ is ranging between 258 Hz - 2502 Hz.

Alveolar Lateral Approximant /l/ :

• The average f 1 of /l/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 315 Hz, 322 Hz and 332 Hz

respectively. The average f 1 of /l/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 345 Hz, 366 Hz and

358 Hz respectively. The average f 1 of /l/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 393 Hz,

417 Hz and 422 Hz respectively. The average f 1 of Kokborok /l/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 315 Hz – 422 Hz.

• The average f 2 of /l/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1537 Hz, 1578 Hz and

1620 Hz respectively. The average f 2 of /l/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1667 Hz,

1704 Hz and 1721 Hz respectively. The average f 2 of /l/ produced by children in a monosyllabic word, polysyllabic word and connected

speech is 1729 Hz, 1738 Hz and 1769 Hz respectively. The average f 2 of Kokborok /l/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 1537 Hz – 1769 Hz.

• The average f 3 of /l/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2426 Hz, 2567 Hz and

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2506 Hz respectively. The average f 3 of /l/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2663 Hz,

2737 Hz and 2702 Hz respectively. The average f 3 of /l/ produced by children in a monosyllabic word, polysyllabic word and connected

speech is 2722 Hz, 2803 Hz and 2783 Hz respectively. The average f 3 of Kokborok /l/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2426 Hz – 2803 Hz.

• The f1, f2 and f3 of Kokborok /l/ is ranging between 315 Hz – 2803 Hz.

Palatal Central Approximant /j/ :

• The average f 1 of /j/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 298 Hz, 329 Hz and 309 Hz

respectively. The average f 1 of /j/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 327 Hz, 352 Hz and

343 Hz respectively. The average f 1 of /j/ produced by children in a monosyllabic word, polysyllabic word and connected speech is 375 Hz,

403 Hz and 408 Hz respectively. The average f 1 of Kokborok /j/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 298 Hz – 408 Hz.

• The average f 2 of /j/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 1273 Hz, 1304 Hz and

1308 Hz respectively. The average f 2 of /j/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 1373 Hz,

1411 Hz and 1373 Hz respectively. The average f 2 of /j/ produced by children in a monosyllabic word, polysyllabic word and connected

speech is 1553 Hz, 1577 Hz and 1543 Hz respectively. The average f 2 of Kokborok /j/ produced by men, women or children either in a

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monosyllabic word, polysyllabic word or connected speech is ranging between 1273 Hz – 1577 Hz.

• The average f3 of /j/ produced by men in a monosyllabic word, polysyllabic word and connected speech is 2316 Hz, 2506 Hz and

2290 Hz respectively. The average f 3 of /j/ produced by women in a monosyllabic word, polysyllabic word and connected speech is 2516 Hz,

2661 Hz and 2493 Hz respectively. The average f 3 of /j/ produced by children in a monosyllabic word, polysyllabic word and connected

speech is 2605 Hz, 2742 Hz and 2615 Hz respectively. The average f 3 of Kokborok /j/ produced by men, women or children either in a monosyllabic word, polysyllabic word or connected speech is ranging between 2290 Hz – 2742 Hz.

• The f1, f2 and f3 of Kokborok /j/ is ranging between 298 Hz – 2742 Hz.

4.2.2 Findings

The acoustic measurements and the close study of the first three formants of all the Kokborok consonants lead to the following findings:

1. The duration of all the Kokborok consonants whether produced in monosyllabic words, polysyllabic words or connected speech either by men, women or children varies from sound to sound because of individual and gender differences. The result of the duration measurements reveals that the Kokborok consonants articulated in connected speech take the lowest duration, in polysyllabic words they take higher duration and in monosyllabic words they take the highest duration. It is because the movement of the articulator is slow in monosyllabic words whereas the movement of the articulator is fast in polysyllabic words and in connected speech. This is in agreement with the claim made by Hardcastle (1973) that ‘the faster the movement of the articulator is, the shorter the closure duration’.

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2. The results of the duration measurements of the Kokborok consonant phonemes show that that men take the lowest duration; children take higher duration and women take the highest duration.

3. In terms of place articulation it is noted that the labial stops have the highest closure duration, coronal stops have lower closure duration and dorso- palatal stops have the next lower closure duration and dorso-velar stops have the lowest closure duration. This is in consonance with the claim made by Maddieson (1991) that the ‘closure duration of a stop reduces with the backness of the tongue’. It reduces in the following order: • Voiceless unaspirated stops → { p > t > k } • Voiceless aspirated stops → { ph > t h > čh > kh } and • Voiced stops → { b > d > ǰ > ɡ }.

4. In terms of voice quality it is noted that the voiceless stops have longer closure duration in comparison to their voiced counterpart. This is in agreement with the claim made by Ladefoged (2002) that ‘voiceless consonants are longer than voiced consonants’. The hierarchy of the closure duration of voiceless and voiced stops is in the following: { p > b}, { t > d }, { ǰ } and { k > ɡ }.

5. In terms of aspiration and unaspiration it is also noted that the unaspirated stops have longer closure duration than their aspirated counterpart. The hierarchy of the closure duration of aspirated and unaspirated stops is given in the following: { p > p h}, { t > t h }, {čh} and { k > kh}

6. Stops in monosyllabic words produced by men, women and children have the longest VOT duration, stops in polysyllabic words have shorter VOT duration and stops in connected speech have the shortest VOT duration.

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7. The VOT for men is the longest, the VOT for women is shorter and the VOT for children is the shortest. It is because the movement of the articulator in case of children is the fastest and movement of the articulator of women is faster than men. This observation supports the Hardcastle’s (1973) claim that ‘the faster the movement of the articulator is, the shorter the VOT’.

8. In terms of place articulation it is observed that the labial stops have the shortest VOT, coronal stops have longer VOT, dorso-palatal stops have next longer VOT and dorso-velar stops have the longest VOT. This is in consonance with the cross linguistic findings i.e. ‘further the back the place of articulation is, the longer the VOT’ (Fischer-Jørgensen, 1954; Peterson and Lehiste, 1960). This is contrary to Hardcastle’s (1973) claim given in the above quotation. The VOT of stops is ranked in the following order: • Voiceless unaspirated stops → { p < t < k } • Voiceless aspirated stops → { ph < t h < čh< kh} and • Voiced stops → { -b< -d < -ǰ < -ɡ}.

9. In terms of aspiration and unaspiration it is observed that the voiceless unaspirated stops have shorter VOT than the voiceless aspirated stops. The hierarchy of the VOT of unaspirated and aspirated stops is given below: { p < p h }, {t < t h}, {čh}, {k < k h }.

10. In terms of voice quality it is seen that the voiceless unaspirated stops have shorter VOT than their counterparts i.e. voiced unaspirated stops. The hierarchy of the VOT of voiceless unaspirated stops and voiced unaspirated stops is given below: {p < -b}, {t < -d }, { -ǰ } and { k < -ɡ }.

11. The study also finds that the relationship in terms of place of articulation, voice quality and aspiration and unaspiration, between closure duration and VOT is reverse i.e. the closure duration decreases as the VOT

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increases and vice versa. The hierarchy of the reverse relationship between closure duration and VOT is in the following:

• Closure duration of unaspirated stops { p > t > k } and VOT { p < t < k } • Closure duration of aspirated stops {ph > t h > čh > kh} and VOT {ph < t h < čh d > ǰ > ɡ} and VOT {-b < -d < -ǰ < -ɡ}.

This observation is in agreement with the claim made by Lehiste (1960) that ‘characteristically VOT increases with the backness of the stop’s place of articulation’. This is also in agreement with the claim made by Maddieson (1997) that ‘the closure duration for bilabial stops is, in general, longer than that of alveolar and velar, possibly due to different degree of air pressure in the cavity behind the constriction’.

12. The coronal fricative /s/ takes longer frication duration than glottal fricative /h/ . The hierarchy, in terms of place of articulation, of coronal and glottal fricatives is → {s > h }.

13. In terms of place of articulation, the labial nasal /m/ takes the longest murmur duration, the coronal nasal /n/ takes shorter murmur duration and the dorso-velar nasal /ŋ/ takes the shortest murmur duration. The hierarchy of the murmur duration of labial, coronal and dorso-velar nasal is → {m > n > ŋ}.

14. In terms of place of articulation, the alveolar lateral approximant /l/ takes the shortest duration, the palatal central approximant /j/ takes longer duration and the alveolar central approximant /r/ takes the longest duration. The hierarchy of the closure duration of alveolar lateral approximant, palatal central approximant and alveolar central approximant is → {l < j < r }.

15. It is also seen that the percentage of duration of consonant phonemes is the highest in monosyllabic words, lower in polysyllabic words and the lowest in connected speech. Further it is also noted that the percentage

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Chapter 4: Acoustic Analysis of the Kokborok Consonants of duration of anterior phonemes is more in comparison to posterior phonemes.

16. The percentage of VOT is the highest in monosyllabic words, lower in polysyllabic words and the lowest in connected speech. It is observed that the percentage of VOT of anterior stops is less in comparison to posterior stops. Further the percentage of VOT of voiceless unaspirated sounds is less than their voiced unaspirated counterparts.

17. The acoustic measurement of the study finds that all the Kokborok consonant phonemes whether produced in isolation, in words or in connected speech either by men, women or children are varied from one another in their formant transition range of the last glottal pulse leading to the voiceless sounds and formant frequency range of the voiced sounds. According to the manner of articulation, the average formant transition range and formant frequency range of the Kokborok consonant phonemes in the vocal tract is given below:

(a) Voiceless Stops

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /p/ range between 854 Hz – 3621 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /p h/ range between 717 Hz - 3680 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /t/ range between 710 Hz – 3507 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /t h/ range between 602 Hz – 2594 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /čh/ range between 674 Hz - 3607 Hz.

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Chapter 4: Acoustic Analysis of the Kokborok Consonants

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /k/ range between 785 Hz – 3470 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /k h/ range between 618 Hz – 3689 Hz.

(b) Voiced Stops

• The f 1, f2 and f 3 of Kokborok /b/ range between 476 Hz – 3914 Hz.

• The f1, f2 and f3 of Kokborok /d/ range between 446 Hz – 3764 Hz.

• The f1, f2 and f3 of Kokborok /ǰ/ range between 416 Hz – 3070 Hz.

• The f1, f2 and f3 of Kokborok /ɡ/ range between 401 Hz – 3751 Hz.

• The f1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /s/ range between 1421 Hz – 3506 Hz.

• The f 1, f2 and f 3 transition of the last glottal pulse leading to the Kokborok /h/ rang between 909 Hz – 2002 Hz.

(d) Nasals

• The f1, f2 and f3 of Kokborok /m/ range between 270 Hz – 2852 Hz.

• The f1, f2 and f3 of Kokborok /n/ range between 295 Hz – 2928 Hz.

• The f1, f2 and f3 of Kokborok /ŋ/ range between 331 Hz –2966 Hz.

(e) Approximants

• The f1, f 2 and f3 of Kokborok /r/ range between 258 Hz - 2502 Hz.

• The f1, f2 and f3 of Kokborok /l/ range between 315 Hz – 2803 Hz.

• The f1, f2 and f3 of Kokborok /j/ range between 298 Hz – 2742 Hz.

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18. The acoustic analysis of the study finds that all the Kokborok nasals have formant frequencies and also they have anti-formant frequencies. From a close study of these, it is noted that:

• The anti-formant of f1 in /m/ is lower and in /n/ is higher. The

hierarchy of the anti-formant of f1 is {m < n}.

• The anti-formant of f2 in /m/ is higher and in /n/ is lower. The hierarchy

of the anti-formant of f2 is {m > n}.

• It is also noted that the sequence between anti-formant of f1 and anti-

formant of f2 of the Kokborok nasals is the reverse one i.e. the anti-

formant of f1 increases from labial < coronal but anti-formant of f2 decreases in the same order such as - labial > coronal.

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Chapter 5 : Conclusions ______

The current study examines and discusses the acoustic aspects of the Kokborok language. It is organized into five chapters and each chapter has several sections. The thesis begins with the introduction. It discusses the methodology, objectives and hypotheses of the research. An account of the acoustic phonetics and acoustic analytic technique of speech sounds are part of discussion in the chapter. In subsequent chapters, the study provides a phonemic inventory of the Kokborok phonemes. Further, it shows that the language has eight phonetically distinctive vowel phonemes, four phonologically distinctive diphthongs, a triphthong and nineteen consonant phonemes. Kokborok consonants are articulated from five different places of articulation: bilabial, alveolar, palatal, velar and glottal and from four different manners of articulation: stop, fricative, nasal and approximant.

The study presents spectrographic sketches of all the Kokborok phonemes and describes each one of them on the basis of the acoustic cues. It also provides the classification, description, distribution and contrast between the phonemes. The acoustic analysis is done within the parameters of duration, formant frequency and formant transition. The duration measurements of all the Kokborok phonemes are done in milliseconds. The formant frequencies and formant transitions are measured in hertz.

Further, the thesis studies the acoustic properties of the Kokborok speech sounds in isolation, in words and in connected speech articulated by men, women and children. The speech sounds that are studied in different word positions as spoken by different speakers lead to variations in durations and formant frequencies. The variations are based on individuals and genders for which evidence is provided from the spectrographic analysis.

195 Chapter 5: Conclusions

The findings reported in this thesis indicate that the sounds whether produced in isolation, in words or in connected speech either by men, women or children are varied from one another in their duration, formant frequency and formant transition range. It is inferred that the variations in speech sounds are attributed to individual speaker differences as well as gender differences. Further, it is also inferred that the variations in articulation of individual speech sounds of Kokborok speaker are attributable to different positions in a word as well as in connected speech.

5.1 Significance and contributions of the study The present study is an attempt to draw the attention of Kokborok speakers towards the importance of scientific investigation in determining the exact quality of Kokborok speech sounds. This study is conducted mainly to examine and discuss the acoustic aspects of the Kokborok speech sounds, as it is felt that there exists no such description of the language.

Kokborok is one of the official languages in the state of Tripura along with Bengali. It has been declared as medium of instruction and the Kokborok speaking students are studying it up to secondary level. It has been introduced as a subject in the foundation course at college level. Tripura University has been providing diploma and advance diploma courses in Kokborok language and literature. The language also is being used on mass-media networks and also in the field of music and drama. Further, many creative works are being published in Kokborok. Despite these merits of the language not significant attention has been paid to study the language linguistically. Except for a few works on phonetics, grammar, lexicography and script, not much is available on other aspects of linguistics. This work as is evident, deals with acoustic study of the Kokborok speech sounds. Thus, it is a significant contribution in the area of Kokborok linguistics.

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Chapter 5: Conclusions

5.2 Suggestions for further research The end of this study is the beginning of new avenues for future research. This study deals with only the acoustic aspect of the Kokborok language but many other aspects are of course remain to be done. These untouched aspects of the language are important. Therefore, we have in our mind the following areas. May be studies on these lines will be useful for Kokborok.

• The present research is only limited to study the segmental aspects of speech. Nothing is available on supra-segmental features, especially its tonal features. Therefore, a comprehensive study on the supra-segmental aspects of the language will be useful. • The present study dealt with the formant frequency measurement of the

Kokborok speech sounds. Many aspects of fundamental frequency (f 0) such as creaky voice and shouting has not been investigated in this study. Therefore, further research especially on those aspects is encouraged. • The acoustic analysis is done with the help of computer and language analysis tools to probe and measure the Kokborok speech sounds. The computer and language analysis tools might be used to visualize the function of vocal apparatus. These also might be used to undertake further research on clinical phonetics as well as speech recognition in different forensic and interrogation cases.

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197

References ______

Abbi, Anvita. 2001. A Manual of Linguistic Field work and Structures of Indian Language . Muenchen: Lincom Europa.

Abercrombie, David. 1965. Studies in phonetics and linguistics. London: Oxford University Press.

Abercrombie, David. 1967. Elements of general phonetics . Edinburgh: Edinburgh University Press.

Acharya, Nirmalendu. 2000. Bhasha Siksha Kakborkok . Agartala: Chanchala Prokashoni.

Acharya, Nitai. 1983/2001. An Easy Kokborok Primer . Agartala: Kokborok Shahitya Samsad.

Acharya, Nitai. 1983b/2007. Shahoj Kokborok Shiksha . Agartala: Yakhrai Publication.

Acharyya, R.K. 2007 (ed). Development of Tribal Languages . Agartala: Tribal Research Institute, Govt. of Tripura.

Ahmed, Daulat and Mohammad Umar. 1897. Kokboroma . Comilla: Amar- jantra.

Amalesh Gope and S. Mahanta. 2015. An acoustic analysis of Sylheti phonemes . Proceedings of the 18th International Conference on Phonetic Sciences.

Anderson, V. B. & Maddieson, Ian. 1994. Acoustic characteristics of Tiwi coronal stops. Journal: UCLA Working Papers in Phonetics, 87, 131-162.

Ansari, Md. 1991. Acoustical measurement of duration of Urdu speech sounds . M. Phil. dissertation, Department of Linguistics, Osmania University, Hyderabad.

Arlotto, Anthony. 1972. Introduction to Historical Linguistics . Boston: Houghton Mifflin Company.

Ashby, Patricia. 1995. Speech Sounds . London: Routledge.

201 References

Baken, R. J. and Robert F. Orlikoff. 2000. Clinical measurement of speech and voice (2nd edn). San Diego: Singular Press.

Ball, M. J. 1993. Phonetics for speech pathology. London: Whurr.

Ball, M. J. and Lowry, O. M. 2001. Methods in clinical phonetics. London: Whurr.

Ball, Martin, and Joan Rahilly. 1999. Phonetics: The Science of Speech . London: Edward Arnold.

Basumatary, Phukan Chandra. 2005. An Introduction to Boro Language . New Delhi: Mital Publication.

Behrens and Blumstein. 1985. Acoustic characteristics of English voiceless Fricative: A descriptive analysis. Journal of Phonetics . 16:3 July 1988, 1358- 98.

Beinum, F. J. K.-V. 1980. Vowel Contrast Reduction: An acoustic and perceptual study of Dutch vowels in various speech conditions . Amsterdam: Academische Pers B V.

Beranek, L. 1949. Acoustic measurement . New York: McGraw-Hill.

Beranek, L. L. 1996. Acoustics . Woodbury, NY. Acoustical Society of America.

Bicldey, C. A., and K. N. Stevens. 1986. Effects of a vocal tract constriction on the glottal source: Experimental and modeling studies. Journal of Phonetics, 14,373-382.

Bladon, A. and Lindblom, B. 1981. Modeling the judgment of vowel quality differences. Journal of the Acoustical Society of America, 69, 1414-22.

Bless, D. M. and Abbs, J. H. 1983. Vocal Fold Physiology: Contemporary research and clinical issues. San Diego: College Hill Press.

Boersma, Paul and David Weenink. 2013. Praat: doing phonetics by computer. http://www.praat.org .

Borden, Gloria J. and Katherine S. Harris. 1980. Speech Science Primer, Physiology, Acoustics and Perception of Speech . London: Williams and Wilkins.

202

References

Boro, M.R. 1990. The Historical Development of Boro Language . Haji: Priyadini Brahma.

Bracewell, R. N. 1986. The Fourier Transform and Its Applications . London: McGraw-Hill Book Company.

Bregman, A. S. 1990. Auditory Scene Analysis: The Perceptual Organization of Sound. Cambridge, MA: MIT Press.

Brosnahan, L., Malmberg, B. 1970. Introduction to Phonetics. Cambridge: Cambridge University Press.

Calvert, D.R. 1992. Descriptive Phonetics . New York, Stuttgart: Thieme.

Campbell, R. 1994. Audiovisual speech: Where, what, when, how? Current Psychology of Cognition, 13, 76-80.

Catford, J. C. 1977. Fundamental Problems in Phonetics . Edinburgh: Edinburgh University Press.

Catford, J. C. 2003. A practical introduction to phonetics . Oxford: Oxford University Press.

Chakarborty, Santosh Kumar. 1981. A Study of Tipra Language . Agartala: Parul Prakashani.

Chakraborty, Santimoy. 2000 . NijeNije Kokborok Shikhun. Agartala: Quick Print.

Charles E.Speaks. 1992. Introduction to sound . Dordrecht, Netherland: Chapman and Hall.

Chatterji, Sunit Kumar. 1926/1971. The Origin and Development of Bangla Language . London: George Allen and Unwin.

Chattopadhyay, Suhas. 1972. Tripurar Kagbarak Bhashar Likhito Rupe Uttaran . Kolkata: The institute of Languages and Applied Linguistics.

Chen. M. 1970. Vowel length variation as a function of voicing of consonants environment. Phonetica : 129-159.

Chen. M. Y. 1995. Acoustic parameters of nasalized vowels in hearing- impaired and normal hearing speakers. Jounurl of the Acoustical Society of America 98, 2443-2453.

203

References

Chiba, T. and Kajiyama, M. 1941. The Vowel: Its nature and structure. Tokyo: Kaiseikan.

Cho, T. & Ladefoged, P. 1999. Variations and universals in VOT: Evidence from 18 Languages. Journal of Phonetics, 27, 207-229.

Chomsky, N., Halle, M. 1968. The Sound Pattern of English. New York: Harper & Row.

Choudhury, Kumud Kundu. 1999. Kokborok Bhashas a Sahitya. Agartala: Akshar Publications.

Choudhury, Kumud Kundu. 2007. Kokborok: A Promising Tribal Language of North-East India. Agartala: Akshar Publications.

Choudhury, Kumud Kundu. 2008. Kokborok Bhasha Sikkhar Ashor . Agartala: Jora Publications.

Choudhury, Kumud Kundu. 2010. Kokborok Dhanibichar . Agartala: Akshar Publications.

Clark, J. and Yallop, C. 1995. An introduction to phonetics and phonology (2 nd edn). Oxford: Blackwell.

Clark, John, Colin Yallop, and Janet Fletcher. 2007. An Introduction to Phonetics and Phonology . 3rd ed. Oxford: Wiley-Blackwell.

Comrie, Bernard. 1987 (ed). The world’s Major Languages . London: Croom Helm.

Cooper, F.S. 1950. Spectrum analysis. Journal of the Acoustical Society of America, 22, 761-2.

Couper-Kuhlen, Elizabeth. 1986. An introduction to English prosody . London: Arnold.

Cruttenden, Alan .1997. Intonation (2 nd edn). Cambridge: Cambridge University Press.

Crystal, D. 1969. Prosodie Systems and Intonation in English. Cambridge: Cambridge University Press.

Crystal, D. 1985. The Cambridge Encyclopedia of Language. Cambridge: Cambridge University Press.

204

References

Crystal, D. 2003. A Dictionary of Linguistics and Phonetics . Oxford. Blackwell.

Crystal, D., Davy, D. 1969. Investigating English Style. London: Longman.

Crystal, T. and A. House. 1988. The duration of American-English stop consonants: an overview. Journal of Phonetics 16: 285–94.

Das, Paresh Chandra. 1967. Kok-robam. Agartala: Education Directorate, Government of Tripura.

Das, Paresh Chandra. 2001. Applied English Grammar and Composition. Kolkata: New Central Book Agency.

Davenport, M., & Hannahs, S. J. 2005. Introducing phonetics & phonology. UK: Hodder Education.

Davis, S. and Mermelstein, P. 1980. Comparison of parametric representations for monosyllabic word recognition in continuously spoken sentences. IEEE Transactions on Acoustics, Speech, and Signal Processing, ASSP 28, 357-66.

Debbarma, Binoy. 1995. Kokborok Kokma. Agartala: Amlan Printers.

Debbarma, Binoy. 1999. Kokborok Terminology [Part-1]. Agartala: Archik Computer.

Debbarma, Binoy. 2001/ 2009. Kokborok-English-Bengali Dictionary . Khumulwng: Language Wing, Education Department, Tripura Tribal Areas Autonomous District Council.

Debbarma, Dasharath. 1980 (2 nd edn). Kog-borok Swrwng . Agartala: Directorate of School Education, Govt of Tripura.

Debbarma, Naresh Chandra. 2006. An Introduction to Kokborok Grammar and Translation . Agartala: Dey Quality Printers.

Debbarma, Rabbindra Kishore. 2004. Kokborok Kokma Kwtal . Agartala: Tripura Printers.

Debbarma, Thakur Radha Mohan. 1900. Kok-borok-ma . Comilla: Chaitanya- Jnatra.

205

References

Debbarma, Thakur Radha Mohan. 1959. Kakborokma, a grammar of the Traipur language. Agartala: Directorate of Education, Government of Tripura.

Debnath, Rupak. 2010. Exploring Highlanders of Tripura and Chittagong Hill Tracts . New Delhi: Akansha Publishing House.

Debnath, Rupak. 2014. Kokborok: Language Origin and Development . Khumulwng: Language Wing, Education Department, Tripura Tribal Areas Autonomous District Council.

Delancey, Scott. 1987. Sino-Tibetan Languages. The World’s Major Languages, 40, p 797-810.

Delattre, P. C., Liberman, A. M., and Cooper, F. S. 1955. Acoustic loci and transitional cues for consonants. Journal of the Acoustical Society of America, 27, 73.

Denes, Peter B. and Elliot N. Pinson. 1993. The speech chain: physics and biology of spoken language . New York: W. H. Freeman.

Devvarman, Naresh Chandra. 2012. An Introduction to Kokborok Language . Agartala: Dey Kokborok Publisher.

Dhar, Prabhas Chandra. 1983/2003. Kokborok Swrwngma: A Grammar of Spoken Kokborok. Agartala: Tribal Culture Research Institute.

Dhar, Prabhas Chandra. 1987. Kok Kuthumma : A kakbarak-Bangla-English Dictionary . Agartala: Tripura Printers.

Dickson, D. R. and W. M. Maue. 1970. Human vocal Anatomy . Springfield: Illinois, Charles C Thomas.

Dilley, L., S. Shattuck-Hufnagel and M. Ostendorf. 1996. Glottalization of vowel-initial syllables as a function of prosodic structure. Journal of Phonetics 24: 423–44.

Dunn and Lacy. 1946. Spectrography. In Acoustic Phonetics (ed) [by D.B Fry] Cambridge: Cambridge University Press.

Egan, J. P. and Hake, H. W. 1950. On the masking pattern of a simple auditory stimulus. Journal of the Acoustical Society of America, 22, 622-30.

Ertmer, D. J. 2001. Emergence of a vowel system in a young cochlear implant recipient. Journal of Speech, Language, and Hearing Research, 44, 803-813.

206

References

Ertmer, D. J., & Maki, J. E. 2000. A comparison of speech training methods with deaf adolescents: Spectrographic versus non instrumental methods. Journal of Speech, Language, and Hearing Research, 4 (6), 1509-1523.

Ertmer, D. J., Stark, R. E., & Karlin, G. R. 1996. Real-time spectrographic displays in vowel production training with children who have profound hearing Loss. American Journal of Speech-Language Pathology, 5 (4), 4-16.

Fahy F. and J. Walker. 1998. Fundamentals of Noise and Vibration. London, E & FN Spon.

Fant, G. 1957. Den akustiska fonetikens grunder . KTH, Inst. för Telegrafi- Telefoni, Rapport nr 7, Taltransmissionslaboratoriet.

Fant, G. 1960. Acoustic theory of speech production. The Hague, Netherlands: Mouton.

Fant, G. 1962. Descriptive analysis of the aspect of speech. Logos 5, 3-17.

Fant, G. 1968. Analysis and synthesis of speech processes. Amsterdam: North-Holland Publ.Co.

Fant, G. 1973. Speech Sounds and Features . Cambridge, MA. MIT Press.

Fischer-Jørgensen, Eli. 1954. Acoustic analysis of stop consonants. Miscellanea Phonetica . Vol. II, 42-59.

Flanagan, J. L. 1965. Speech Analysis Synthesis and Perception. Berlin: Springer Verlag.

Forrest, K., Weismer, G., Milenkovic, P., and Dougall, R. N. 1988. Statistical analysis of word-initial voiceless obstruents: Preliminary data. Journal of the Acoustical Society of America, 84, 115-23.

Fromkin, Victoria, Robert Rodman and Nina Hyams. 2007. An introduction to Language . Boston, MA and London: Thomson/Wadsworth.

Fry, D.B. 1976. Acoustic Phonetics. Cambridge: Cambridge University Press.

Fry, D.B. 1979. The Physics of Speech. Cambridge: Cambridge University Press.

Fucci, D.J. and N.J. Lass. 1999. Fundamentals of Speech Science. London: Allyn and Bacon.

207

References

Fujimura, O. 1961. Bilabial stop and nasal consonants: a motion picture study and its implications. JSHR 4: 233-47.

Fujimura, O. 1962. Analysis of nasal consonants. Journal of the Acoustical Society of America, 32, 1865-75.

Fujimura, O. 1973 (ed). Three dimensions of linguistic theory . Tokyo: TEC.

Giegerich, Heinz. 1992. English phonology . Cambridge: Cambridge University Press.

Gimson, A.C. 1970/1975. A Practical Course in English Pronunciation London: Edward Arnold.

Goswami, G.C. 1966. In Introduction to Assammese Phonology . Poona: Deccan College.

Grierson, G.A. 1903/1967. Linguistic Survey of India 3:2. Delhi: Motilal Banarasidass.

Grunwell, P. 1987. Clinical Phonology (2 nd ed). London: Croom Helm.

Guion, S. G. 1998. The role of perception in the sound change of velar palatalization. Phonetica, 55, 18, 52.

Halle, M., Hughes, C. & Radley, J. P. 1957. Acoustic properties of stop consonants. Journal of Acoustical Society of America 29, 107-116.

Halliday, M.A.K. 1967. Intonation and Grammar in British English. The Hague: Mouton.

Halliday, M.A.K. 1970. A Course in Spoken English: Intonation. Oxford: Oxford University Press.

Hardcastle, W. J. 1973. Some observations on the tense-lax distinction in initial stops in Korean. Journal of Phonetics , 1, 263-271.

Hardcastle, W. J. 1976. The Physiology of Speech Production . New York: Academic Press.

Hardcastle, W. J. and John Laver (eds.). 1997. The Handbook of Phonetic Sciences . Oxford: Blackwell.

208

References

Harnsberger, J. D. 2001. The perception of Malayalam nasal consonants by Marathi, Punjabi, Tamil, Oriya, Bengali, and American English listeners: A multidimensional scaling analysis. Journal of Phonetics, 29, 303-27.

Harrington, Jonathan and Cassidy, Steve. 1999. Techniques in Speech Acoustic . Dordrecht, Netherland: Kluwer Academic Publishers.

Haughton, P. 2002. Acoustics for Audiologists. London: Academic Press.

Heinz, J. M. and Stevens, K. N. 1961. On the properties of voiceless fricative consonants. Journal of the Acoustical Society of America, 33, 589-96.

Hess, W. 1983. Pitch Determination of Speech Signals: Algorithms and Devices . Berlin: Springer-Verlag.

Hewlett, N. and Beck, J. 2006. An introduction to the science of phonetics. Mahwah, NJ: Lawrence Erlbaum Associates.

Hirano, M. 1981. Clinical Examination of Voice . Wien / New York: Springer Verlag.

Hodson, B.W. 1980. The Assessment of Phonological Processes. Danville, IL: Interstate Inc.

Hughes and Halle. 1956. Acoustic Properties of Stop Consonants . JASA, vol.29, no. 1, 107-116.

Hyman, L. 1975. Phonology: Theory and Analysis . New York: Holt, Rinehart and Winston.

Ingram, D. 1981. Procedures for the Phonological Analysis of Children's Language. Baltimore, MD: University Park Press.

IPA (International Phonetic Association). 1999. Handbook of the International Phonetic Association . Cambridge: Cambridge University Press.

J. K., Ogden, R. A. and Temple, R. (eds.) Papers in laboratory phonology VI. Cambridge: Cambridge University Press, pp. 237-252.

Jacewicz, Ewa, Joseph Salmons and Robert A. Fox. 2007. Vowel duration in three American English dialects. American Speech 82: 367–85.

Jacquesson, Francois. 2008. A Kokborok Grammar . Agartala: Kokborok Tei Hukumu Mission.

209

References

Jakobson, R., Fant, G., and Halle, M. 1952. Preliminaries to Speech Analysis. Cambridge, MA: MIT Press.

James Hillenbrand, Laura A. Getty, Michael J.Clark, and Kimberlee Wheeler. 1994/1995. Acoustic characteristics of American English Vowels. Department of Speech Pathology and Audiology, Western Michigan University, Kalamazoo, Michigan 49008.

Jha, Sunil Kumar. 2001. Maithili: Some Aspects of Its Phonetics and Phonology . Delhi: Motilal Banarsidass.

Johnson, K. 1992. Acoustic and auditory analysis of Xhosa clicks and pulmonics. UCLA Working Papers in Phonetics, 83, 33-47.

Johnson, K. 2008. Quantitative Methods in Linguistics. Oxford: Wiley- Blackwell.

Johnson, K., Ladefoged, P., and Lindau, M. 1993. Individual differences in vowel production. Journal of the Acoustical Society of America, 94, 701-14.

Johnson, Keith. 2003. Acoustic and Auditory Phonetics (2nd ed). Oxford: Wiley Blackwell.

Jones, Daniel, James Hartman, Jane Setter, and Peter Roach. 2006. English Pronouncing Dictionary . 17th ed. Cambridge: Cambridge University Press.

Jones, W.E. and John Laver (eds.). 1973. Phonetics in Linguistics . London: Longman.

Joos, M. 1948. Acoustic Phonetics. Language , 24, 1-136.

K.Wu and D. Childers. 1991. Gender recognition from speech. Journal of the Acoustical Society of America, 90, 1828-1856.

K.Wu and D. Childers. 1991. Segmentation of speech using speaker identification. Pro. IEEE Int. Conf. ASSP, I: 161-164.

Kahane, J., Folkins, J. 1984. Atlas of Speech and Hearing Anatomy. Columbus, OH: Bell & Howell.

Keating, P. 1984. Phonetic and phonological representation of stop consonant voicing. Language, 60 , 286-319.

210

References

Kelly, John and John Local. 1989. Doing phonology . Manchester: Manchester University Press.

Kenstowicz, M. 1994. Phonology in generative grammar. Oxford: Blackwell.

Kent, R. D. & Charles, R. 1995. Acoustic analysis of speech. San Diego: Singular Publishing Group.

Kent, R.D. 1997. The Speech Sciences. San Diego, CA: Singular Publishing Group.

Kiani, H. Z., Bukhari, N., Ahmed, J. & Hameed, N. 2012. Acoustic analysis of Hindko stops. Kashmir Journal of Language Research, 15 (2) , 135-150.

Kim, Amy, Seung Kim, Palash Roy and Mridul Sangma. 2011. The Tripura of Bangladesh: A Sociolinguistic Survey . Dhaka: SIL International.

Klatt, D. H. 1975. Voice onset time, friction, and aspiration in word-initial consonants clusters. Journal of Speech and Hearing Research, 18 , 686-706.

Klatt, D. H. and Klatt, L. 1990. Analysis, synthesis, and perception of voice quality variations among female and male talkers. Journal of the Acoustical Society of America, 87, 820-57.

Kostic, D., and Das, R.S. 1972. A Short Outline of Bengali Phonetics . Calcutta: Statistical Publishing Society.

Labov, William. 1972. Language in the inner city: studies in the Black English Vernacular . Philadelphia: University of Pennsylvania Press.

Ladd, D. Robert. 1996. Intonational phonology . Cambridge: Cambridge University Press. Ladefoged et al. 1978. What are Linguistic sounds made of ? Language , 56:3, 485-502.

Ladefoged, P., DeClerk, J., Lindau, M., and Papcun, G. 1972. An auditory- motor theory of speech production. UCLA Working Papers in Phonetics, 22, 48-75.

Ladefoged, Peter and Anthony Traill. 1994. Clicks and their accompaniments. Journal of Phonetics 22: 33–64.

211

References

Ladefoged, Peter and Keith Johnson. 2011/2006/ 2002/2001. A course in phonetics. Boston: Wadsworth.

Ladefoged, Peter and Maddieson, Ian. 1996. Sounds of the world’s languages . Oxford: Blackwell.

Ladefoged, Peter. 1967. Three Areas of Experimental Phonetics . London: Oxford University Press.

Ladefoged, Peter. 1971. Preliminaries to Linguistic Phonetics . Chicago: The University of Chicago Press.

Ladefoged, Peter. 1996. Elements of Acoustic Phonetics . 2nd ed. Chicago: University of Chicago Press.

Ladefoged, Peter. 1999. American English, in IPA 1999: 41–4.

Ladefoged, Peter. 2003. Phonetic Data Analysis: An Introduction to Fieldwork and Instrumental Techniques . Oxford: Wiley-Blackwell.

Ladefoged, Peter. 2005. Vowels and consonants: An introduction to the sounds of languages (2 nd ed). Oxford: Blackwell.

Ladefoged, Peter. 2006. A course in phonetics (5th edn). Boston, MA: Thomson/ Wadsworth.

Lahiri, Aditi and Henning Reetz. 2002. Underspecified recognition. In Carlos Gussenhoven and Natasha Warner (eds). Laboratory Phonology , 38, 245-294.

Lambacher, S., Martens, W., Nelson, B., and Berman, J. 2001. Identification of English voiceless fricatives by Japanese listeners: The influence of vowel context on sensitivity and response bias. Acoustic Science & Technology, 22, 334-43.

Lass, N. J., Ed. 1996. Principles of Experimental Phonetics . London: Mosby.

Laufer, A. 1991. Does the 'voiced epiglottal plosive' exist? Journal of the International Phonetic Association 21, 44-45.

Laver, J. 1980. The Phonetic Description of Voice Quality , Cambridge: Cambridge University Press.

Laver, J. 1994. Introduction to theoretical Phonetics . Cambridge: Cambridge University Press.

212

References

Laver, J. 1994. Principles of Phonetics . Cambridge: Cambridge University Press.

Lawrence J. Raphael, Ph.D, Gloria. Borden, Ph.D, Katherine S. Harris, Ph.D. 2007. Speech Science Primer: Physiology, Acoustic and Perception of Speech. Sydney: Wolters Kluwer.

Lecumberri, Maria Luisa Garcia and J. A. Maidement. 2000. English transcription course . London: Arnold.

Lehiste, Ilse. 1960. Segmental and syllabic quantity in Estonian American studies in Uralic Lingustics,1 . Bloomington: Indiana University.

Lehiste, Ilse. 1967. Readings in acoustic phonetics . Cambridge, Massachusetts: MIT Press.

Lehiste, Ilse. 1970. Suprasegmentals . Massachusetts: MIT Press.

Lewin, T.H. 1869. The Hill Tracts of Chittagong and the dwellers Therein . Kolkata: Calcutta.

Lieberman, P., Blumstein, D. 1988. Speech Physiology, Speech Perception and Acoustic Phonetics. Cambridge: Cambridge University Press.

Lin, Q. 1990. Speech production theory and articulatory speech synthesis. Ph.D. thesis, Department of Speech Communication and Music Acoustics, Royal Institute of Technology, Stockholm.

Lindau, M. 1978. Vowel Features. Language, 54: 541-63.

Lindau, M. 1984. Phonetic differences in glottalic consonants. Journal of Phonetics, 12, 147, 55.

Lisker, L. & Abramson, A. S. 1964. A cross-language study of voicing in initial stops: Acoustical measurements. Word, 20, 384-422.

Local, J. K. and Lodge, K. R. 2004. 'Some impressionistic and acoustic observations on the phonetics of [ATR] harmony in a speaker of a dialect of Kalenjin.' Journal of the International Phonetic Association 34: 1-16.

Lyons, R. F. 1982. A computational model of filtering, detection and compression in the cochlea. Proceedings of the IEEE International Conference on Acoustics, Speech and Signal Processing, 1282-5.

213

References

Lyons, R. F. 1997. Understanding Digital Signal Processing. Reading, MA: Addison Wesley.

Macken, M. A. 1995. 'Phonological acquisition.' In Goldsmith, J. A. The handbook of phonological theory. Oxford: Blackwell, pp. 671-696.

Maddieson, Ian. 1984. Patterns of Sounds . Cambridge: Cambridge University Press.

Maddieson, Ian. 1991. Testing the universality of phonological generalization with a phonetically specified segment database: Results and limitations. Phonetica, 48 , 193-206.

Maddieson, Ian. 1997. Phonetic universals. In W. J. Hardcastle, & J. Laver (eds.) The Handbook of Phonetic Science (pp. 619-639). Oxford: Blackwell.

Malmberg, Bertil. 1963. Phonetics . New York: Dover Publication, Inc.

Malmberg, Bertil. 1974. Manual of Phonetics . Massachusetts. MIT Press.

Marple, L. 1987. Digital Spectral Analysis with Applications. Englewood Cliffs, NJ: Prentice Hall.

McCawley, J.D. 1978. What is a tone language? In Fromkin, Y.A. (ed.), Tone: A Linguistic Survey. New York: Academic Press, 113-13I.

McDonough, J. and Ladefoged, P. 1993. Navajo stops. UCLA Working Papers in Phonetics, 84, 151–64.

Morse, P. M. 1948. Vibration and sound. New York: McGraw-Hill.

Mrayati, M., Carré, R., and Guérin, B. 1988. Distinctive regions and modes: A new theory of speech production. Speech Communication, 7, 257-86.

Munro Mackenzie, M.D, 1978.Modern English Pronunciation Practice. London: Longman.

Mustafa, K.S. 2000. A Descriptive Grammar of Dakkhini . New Delhi: Munshiram Manohar Lal Publishers Pvt. Ltd.

Naggama, Reddy, K. 1981. Telugu Consonants and Vowels: An Instrumental Study, Ph.D. Thesis, Edinburgh University.

214

References

Naggama, Reddy, K. 1988. The duration of Telugu Speech Sounds: An acoustic Study . JETE.34. (1:3).

Naggama, Reddy, K. and Fatihi, A.R. 2002. Studies in Phonetics and Phonology : With reference to Indian Language . Aligarh: ESS, ESS publication.

Nihlani, Paroo K. 1972. The articulation of Stops in Sindhi: A Physiological and Aerodynamic Study. CIEFL, Hyd.

O. Shaughnessy, D. 1987. Speech Communication: Human and machine. Reading, MA: Addison-Wesley.

Ogden, Rechard. 2009. An Introduction to English Phonetics . Edinburgh: Edinburgh University Press.

Oppenheim, A. V. 1975. Digital Signal Processing: Study Guide (parts 1 & 2) . Cambridge, Mass., USA: Massachusetts Institute of Technology.

P. Sarmah, L. Dihingia, D. Choudhury. 2015. An Acoustic Study of Bodo Vowels . Himalayan Linguistics, Vol 15 (1) Painter, Colin. 1979. An Introduction to Instrumental Phonetics . Baltimore: University Park Press.

Palmer, F. R. 1970. Prosodic analysis. London: Oxford University Press.

Pandeli, H., J. Eska, M.J. Ball and J. Rahilly. 1997. Problems of phonetic transcription: the case of the Hiberno-English flat alveolar fricative. JIPA 27:65-75.

Perkins, W. H. and R. D. Kent. 1986. Textbook of Functional Anatomy of Speech, Language, and Hearing . London: Taylor and Francis.

Peterson, G. E. & Lehiste, I. 1960. Duration of syllable nuclei in English. Journal of the Acoustical Society of America, 3, 693-703.

Peterson, G.E, and Barney. 1952. Control methods used in a study of the vowels from fifty male speakers. Journal of the Acoustical Society of America, 32, 693-703.

Peterson, G.E. and Shoup, J.E. 1966 a. The elements of an acoustic Phonetics Theory. Journal of Speech and Hearing Research: 9, 68-99.

215

References

Peterson, G.E. and Shoup, J.E. 1966. A Physiological theory of Phonetics. Journal of Speech and Hearing Research: 9, 5-67.

Pickett, J. M. 1999. The acoustics of speech communication fundamentals, speech perception theory, and technology. Boston: Allan and Bacon.

Pickett, J. M. 1999. The Acoustics of Speech Communication: Fundamentals, Speech Perception Theory, and Technology . Boston: Allyn and Bacon.

Pike, K. L. 1943. Phonetics. Ann Arbor: University of Michigan Press.

Pike, K.L. 1948. Tone Languages. Ann Arbor, MI: University of Michigan Press.

Pike, K.L. 1962. Practical phonetics of rhythm waves. Phonetica 8, 9-30.

Pike, Kenneth L. 1943. Phonetics: a critical analysis of phonetic theory and a technic for the practical description of sounds . Ann Arbor: University of Michigan Press.

Potter, R. K., Kopp, G. A., and Green, H. 1947. Visible Speech. Dordrecht: Van Nostrand.

Prout, J. H. and G. R. Bienvenue. 1990. Acoustics for you . Malabar, Florida: Krieger Publishing Company.

Pulgram, E. 1959. Introduction to the Spectrography of Speech . The Hague, Netherlands: Mouton.

Pullum, Geoffrey K. and William A. Ladusaw. 1996. Phonetic symbol guide (2 nd edn). Chicago: University of Chicago Press.

Pushpa, Karapurkar Pai. 1972. Tripuri Phonetic Reader . Mysore: Central Institute of Indian Languages.

Pushpa, Karapurkar Pai. 1976. Kokborok Grammar . Mysore. Central Institute of Indian Languages.

Rabiner, L. R. and R. W. Schafer. 1978. Digital Processing of Speech Signals . Englewood Cliffs, NJ: Prentice-Hall.

Rashid, Haroon-ur & Akhtar, Raja Nasim. 2014. A Phonemic and Acoustic Analysis of Hindko Oral Stops . AMU, Aligarh, UP, India. Aligarh Journal of Linguistics.

216

References

Rayleigh, J. W. S. 1896. The Theory of Sound. London: Macmillan; reprint 1945, New York: Dover.

Reang, Gitya Kumar. 2007. Kaubru Abhidhan [Kaubru Dictionary]. Agartala: Tribal Research Institute.

Roach, Peter. 2000. English Phonetics and Phonology: A Practical Course. 3 rd ed. Cambridge: Cambridge University Press.

Rogers, Henry. 2000. The sounds of language: an introduction to phonetics . New York: Longman.

Rossing T. 1990. The Science of Sound . Reading, MA: Addison-Wesley.

Ryalls, J. 1996. An Introduction to Speech Perception. San Diego, CA: Singular Publishing Group.

S. Mahanta. 2012. Assamese: Language Description . Journal of the International Phonetic Association. 42.2, 217-224.

Saha, Sudhanshu Bikash. 1988. Origin and Structure of Kokborok: a Tribal Language . Agartala: Rupali Publishing.

Seikel, J.A., King, D., Drumright, D. 1997. Anatomy and Physiology for Speech and Language. San Diego, CA: Singular Publishing Group.

Sethi, J. and D.V. Jindal, 1993. A Handbook of Pronunciation of English Words. New Delhi: Prentice –Hall of India.

Shannon, C. E. and Weaver, W. 1949. The Mathematical Theory of Communication. Urbana: University of Illinois.

Shockey, Linda. 2003. Sound patterns of spoken English . Oxford: Blackwell.

Shoup, J. E. and Pfeiffer, L.L. 1976. Acoustic characteristics of speech sounds . In Lass 1976: 171-224.

Sivertsen, Eva. 1960. Cockney phonology . Oslo: University Press and New York: Humanities Press.

Slomanson, Peter and Michael Newman. 2004. Peer group identification and variation in New York Latino English laterals. EWW 25: 199–216.

217

References

Stetson, R.H. 1951. Motor Phonetics (2 nd ed). Amsterdam: North Holland Publishing Co.

Stevens, K. N. & Bloomstein, S. E. 1978. Invariants cues for place of articulation in stop consonants. Journal of the Acoustical Society of America, 64 , 1358-1368.

Stevens, K. N. 1987. Interaction between acoustic sources and vocal-tract configurations for consonants. Proceedings of the Eleventh International Conference on Phonetic Sciences, 3, 385-9.

Stevens, K. N. 1989. On the quantal nature of speech. Journal of Phonetics, 17, 3-46.

Stevens, K. N. 1993a. Modeling affricate consonants. Speech Communication, 13, 33-43.

Stevens, K. N. 1993b. Models for the production and acoustics of stop consonants. Speech Communication, 13, 367-375.

Stevens, K. N. 1999. Acoustic Phonetics. Cambridge, MA: MIT Press.

Stevens, K. N., and S. E. Blumstein. 1994. Attributes of lateral consonants. Journal of the Acoustical Society of America, 95, 2875.

Stevens, K. N., Keyser, S. J. & Kawasaki, H. 1986. Toward a phonetic and Sutherland, H.C. 1860. Tipperah. In Calcutta Review , Vol. XXXV, No.70, Kolkata.

Stevens, S. S. 1957. Concerning the form of the loudness function. Journal of the Acoustical Society of America, 29, 603-6.

Stone, M. 1991. Toward a model of three-dimensional tongue movement. Journal of Phonetics, 19, 309-20.

Strevens, P. 1960. Spectra of fricative noise in human speech. Language and speech , 3, 32-49.

Sweet, Henry. 1877. A Hand book of Phonetics . Oxford: Clarendon Press.

Trask, R.L. 1996. A Dictionary of Phonetics and Phonology . London: Routledge.

218

References

Traunmuller, H. 1981. Perceptual dimension of openness in vowels. Journal of the Acoustical Society of America, 69, 1465-75.

Tripura, Ajita. 2011. A comparative study of Kokborok, English and Bengali Language. Agartala: Tribal Research and Cultural Institute, Govt. of Tripura.

Truby, H. M., J. F. Bosma, J. Lind and P. Karlberg. 1960. Infant Cry Sounds: a Visual-Acoustic Analysis Technique. Stockholm, (The Wenner-Gren Research Library).

Warren, D.W. 1976. Aerodynamics of speech production. In Lass 1976: 105- 37.

Weiner, EE 1979. Phonological Process Analysis (PPA). Baltimore, MD: University Park Press.

Wells, J. C. 2006. English intonation: an introduction . Cambridge: Cambridge University Press.

Wells, John. 2008. Longman Pronunciation Dictionary . 3rd ed. Harlow: Pearson ESL.

Wolfram, Walt and Ralph W. Fasold. 1974. The study of social dialects in American English . Englewood Cliffs, NJ: Prentice Hall.

Zelman, Willard. 1998. Speech and Hearing Science, Anatomy and Physiology . 4th ed. Englewood Cliffs: Prentice-Hall.

Zimmerman, S.A., and Sapon, S.M. 1958. Note on vowel duration seen cross- linguistically. Journal of the Acoustical Society of America, 30, 152-53.

Zsiga, Elizabeth C. 1994. Acoustic evidence for gestural overlap in consonant Sequences. Journal of Phonetics 22: 121–40.

Zue, V. W. 1989. Speech Spectrogram Reading: An acoustic study of English words and sentences , University of Edinburgh: University of Edinburgh.

Zwicker, E. 1961. Subdivision of the audible frequency range into critical bands . Journal of the Acoustical Society of America, 33, 248.

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Appendix ______

Appendix – 1

Sample Data of the Kokborok Speech Sounds

Sounds in Isolation : → [/i , e , a , ə , ɯ , ɔ, o , u/], [/ai/, /au/, / ɔi/, /ua/], [/uai/] and [/p, p h, b, t, t h, d, čh, ǰ, k, kh, ɡ, s, h, m, n, ŋ, r, l, j/].

Sounds in word : → [/mil/, /mel/, /mal/, /m əla/, /m ɯlɯk/, /m ɔhl/, /mol/, /muluk/, /baih/, /b ɔih/, /bauti/, /kuak/, čhuaik ɔl/, /pa/, /apa/, /ta/, /ata/, /ka/, /akar/, /ba/, /haba/, /da/, /hada/, /ǰa/, /raǰa/, / ɡa/, /aɡar/, /p ha/, /ap ha/, /t ha/, /at haŋ/, / čha/, /ka čha/, /k ha/, /ak hata/, /sa/, /kasa/, /ha/, /kaham/, /ham/, /lama/, /han/, /lana/, /ha ŋ/, /la ŋa/, /la/, /kalam/, /ra/, /kara/, /ja/, /aja ŋ/].

Sounds in Connected Speech : → [/b ɔ belai biɡra/, /ani m əmla kɯrɯi/, /b ɔnɔ sadi ǰotɔnɔ kubui/, /b ɔ auli ɔ čhuak nɯŋɔi phaikha/, /a ŋ uaikre čhahuo/, /puk hur kinar ɔ ta a čhukdi/, /b ɔ san ǰao n ɔɡɔ tɔŋdi/, /apha t haihc huk čhahk ha/, /b ɔnɔ sadi ani həmbai/, /nini mu ŋ tamɔ/?, /b ɔhr ɔk hamaja k ɯlai t ɔŋɔ/].

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Appendix – 2

Sample Spectrograms

Sample Spectrograms of Vowels

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Sample Spectrograms of Diphthongs

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Sample Spectrograms of Triphthongs

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Sample Spectrograms of Obstruent Consonants

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Sample Spectrograms of Sonorant Consonants

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Sample Data Analysis Table

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Appendix - 4 Sample Calculation of Anti-formant

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Sample Photo Album

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