Experimental Study of Vowels in Nagamese, Ao and Lotha: Lan- guages of Nagaland Joyanta Basu, Tulika Basu, Soma Khan, Tapan Kumar Basu Madhab Pal, Rajib Roy Centre for Development of Advanced Computing Department of Electrical Engineering, (CDAC), Kolkata Academy of Technology Salt Lake, Sector – V, Kolkata, India Aedconagar, Hooghly, West Bengal, India {joyanat.basu,tulika.basu, soma.khan, [email protected] madhab.pal, rajib.roy}@cdac.in an area of 255,511 square kilometers (98,653 sq Abstract mi) i.e. about seven percent of India's total area. As of 2011 they had a population of 44.98 million, This paper describes the vowels characteris- about 3.7 percent of India's total population. Alt- tics of three languages of Nagaland namely hough there is great ethnic and religious diversity Nagamese, Ao and Lotha. For this study, nu- within the seven states, they bear similarities in the cleus vowel duration, formant structure (1st nd political, social and economic spheres (Wikipedia, and 2 formant i.e. F1 and F2) and intensity 2015). According to the 1971 census there are of vowels are investigated and analyzed for these languages. This paper includes the nasal about 220 languages spoken in these states, be- context for different vowels and tries to exam- longing mainly to three language families, namely ine its importance in different languages. A Indo Aryan, Sino-Tibetan and Austro-Asiatic. The detailed analysis is carried out for six vowels Indo-Aryan is represented mainly by Asamiya and namely for readout Bangla, Austro-Asiatic is represented mainly by speech of Nagamese, Ao and Lotha. Result Khasi and the Sino-Tibetan family of languages is shows that the vowel duration and formants represented by Tani group of languages (Apatani, play important roles in differentiating vowels Galo, Nyishi etc.), Angami, Chakesang, Kuki, Ma- characteristics. On the other hand, intensity of nipuri, Mizo, Kokborak etc. vowels do not play significant role in the The entire North-east India is enclosed by major characteristics of the vowels across the lan- international borders of Bhutan, Nepal and China guages is observed. This initial study unveil in the North and North-East, Bangladesh in South the importance of vowels characteristics and may help to do research and development in and West and Myanmar in East. This region is the area of language identification, synthesis, therefore very sensitive from the point of view of speech recognition of three north-eastern lan- national security and national integrity. guages of Nagaland. Among the eight states of north-east India, the states that share far east international borders with 1 Introduction Myanmar i.e. Manipur and Nagaland are getting much importance now-a-days due to unrest social Culture and language diversity is one of the inter- and political situations. Since the last decade, esting phenomena in North-Eastern states of India. spread of recent communication mediums like mo- The seven states (i.e. Arunachal Pradesh, Assam, biles, telephones and VoIP are supporting spoken Meghalaya, Manipur, Nagaland, Mizoram and communication in regional north-east languages. Tripura) except Sikkim of north-east India cover Speech data in these communications has become 315 D S Sharma, R Sangal and A K Singh. Proc. of the 13th Intl. Conference on Natural Language Processing, pages 315–323, Varanasi, India. December 2016. c 2016 NLP Association of India (NLPAI) necessary for surveillance purposes. But detailed world. Their numbers, acoustic characteristics, par- analysis on any speech data depends largely on ticularly timbral ones need to be well defined for pre-defined knowledge on the spoken language and technology development (Tulika Basu and Arup availability of language resources. Unfortunately Saha, 2011). For this work we have considered very little prior works have been done on the lan- three important parameters of vowels like For- guages of Nagaland and Manipur. mants, Nucleus Vowel Duration and Intensity. Nu- In this study, we are mainly concentrating on cleus vowel is defined as the steady state of the major languages of the Nagaland state. These are vowel along with the two transitions (Rajib Roy, Nagamese, Ao and Lotha. Apart from the basic Tulika Basu, Arup Saha, Joyanta Basu, Shyamal language grammar, phonetic reader and dictionary Kr Das Mandal, 2008) as in figure 1. very few linguistic resources are available for One way to objectively differentiate vowels is to study and research purposes. Among the previous examine the first two formant frequencies, namely resources of Ao language, an important and detail 1st formant (F1) and 2nd formant (F2), which study has been reported on the phonetic and pho- roughly correlate with tongue height and tongue nological description of the Mongsen dialect of Ao position respectively (G. E. Peterson and H. L. (Alexander R. Coupe, 2003). The study is well Barney. 1952). In general high first formant is as- supported by experimental findings as well as au- sociated with narrow tongue constriction near the thor’s personal insights on the studied language. glottis. Similarly second formant frequency is in- Lotha language is very rarely studied till date. Dif- creased as the constriction moves forward (K. N. ferent aspects of Lotha language has been docu- Stevens and A. S. House. 1961). Using F1 and F2 mented in (Chiang Chen Shan, 2011) which is the it is possible to properly place them in a vowel di- only available study on this language. Nagamese, agram. the communication language (lingua franca) of This study will help further for different applica- Nagaland is quite well studied since 1921 by J.H. tions like speech synthesis, language identification, Hutton. The first ever linguistic study of Nagamese speech recognition etc. in the target languages. has been reported by M. V. Sreedhar (1974) in “Naga Pidgin: A Sociolinguistic Study of Inter- lingual Communication Pattern in Nagaland”. This was followed by “Standardized Grammar of Naga Pidgin” by Sreedhar himself in 1985. B K Boruah's “Nagamiz Kothalaga Niyom - A Primary Grammar on Nagamese” (1985) and “Nagamese: The Lan- guage of Nagaland” (1993) are also some relevant studies to understand the basic structure and nature of Nagamese language. The last reported study on Nucleus Vowel /a/ Nagamese language is “The structure of Nagamese Figure 1. Nucleus Vowel Duration the contact language of Nagaland” (2003) by Ajii Kumar Baishya of Assam University. However, the three languages Ao, Lotha and 3 Languages of Nagaland Nagamese were never studied together to frame out similarities or differences in phoneme charac- Nagaland is a state in Northeast India. It borders teristics. Moreover except Ao language, unfortu- the state of Assam to the west, Arunachal Pradesh nately very little work on acoustic analysis has and part of Assam to the north, Myanmar to the been done so far in two other languages. east and Manipur to the south. The state capital is Kohima, and the largest city is Dimapur. It has an 2 Purpose of the Study area of 16,579 square kilometres (6,401 sq mi) with a population of 1,980,602 as per the 2011 Main purpose of the study is to find out vowels Census of India. Nagaland is the home to 16 indig- characteristics of the major languages of Nagaland enous tribes namely Ao, Angami, Chang, Konyak, i.e. Nagamese, Ao and Lotha. Vowels possess one Lotha, Sumi, Chakhesang, Khiamniungan, Dimasa of the defining structures of any language in the Kachari, Phom, Rengma, Sangtam, 316 Yimchunger,Kuki, Zeme-Liangmai (Zeliang) and For this study we have selected three important Pochury as well as a number of sub-tribes. Each languages of Nagaland i.e. Nagamese, Ao and tribe is unique in character with its own distinct Lotha. customs, language and dress. Nagaland is one of three states in India where most of the population 3.1 About Ao Language is Christian (Wikipedia Nagaland). As per Grierson's classification system, Naga Ao is one of the important languages in Nagaland. languages can be grouped into three groups- Ao is spoken by a large number of people in the Western, Central and Eastern Naga Groups. The state. Mongsen, Chungli, Chanki etc. are promi- Western Group includes Angami, Chokri and nent among the Ao dialects. Among all the dia- Kheza. The Central Naga group consists of Ao, lects, Chungli is the widely spoken one and people Lotha and Sangtam, whereas Eastern Group com- of other Ao dialects can speak Chungli Ao but not prises of Konyak and Chang. In addition, there are vice versa. The inhabitants of the Mokokchung Naga-Bodo group illustrated by Mikir language, district mainly converse in this language. The and Kuki group of languages illustrated by vowel inventory of Chungli Ao is like this: Sopvama (also called Mao Naga) and Luppa lan- /ɨ/, // (Bruhn Daniel, 2009). Nasality guages. These languages belong mostly to the Si- is not phonemic in Ao. It is a tonal language with 3 no-Tibetan language family. Since most of these contrasting lexical tones: high, mid and low. All languages are mutually unintelligible, people de- are register tones. pend on a pidgin language called Nagamese for communication. English has been used as the offi- 3.2 About Lotha Language cial language of the Nagaland state and it is quite The Lotha language is part of the Sino-Tibetan popular among the educated mass of Nagaland. language family, spoken by approximately 166,000 But Nagamese is used as the lingua franca among people in Wokha district, west-central Nagaland, the various ethnic groups in the state. The lan- India. It is centered in the small district of Wokha. guages of Nagaland state are not included in the This district has more than 114 villages such as scheduled list of twenty two languages in India, Pangti, Maraju (Merapani), Englan, Baghty (Pakti) many of them spoken by dwindling number of and others, where the language is widely spoken speakers.