ICPhS XVII Regular Session Hong Kong, 17-21 August 2011
BREATHINESS CONTRASTS IN CONSONANTS AND VOWELS: A COMPARATIVE STUDY OF GUJARATI AND WHITE HMONG
Sameer ud Dowla Khana & Christina M. Espositob
aBrown University, USA; bMacalester College, USA [email protected]; [email protected]
ABSTRACT voiced aspirated consonant) from [CV ] (with a breathy vowel), if at all? Only a small handful of languages are known to The current study answers the following distinguish breathy and modal voice in both questions, using acoustic and electroglottographic consonants and vowels. Two of these languages, data from Gujarati and White Hmong: Gujarati and White Hmong, boast CV sequences in which phonetic breathiness can be phonologically Is consonant breathiness distinguished from associated either with the consonant or with the vowel breathiness in the timing/duration of its vowel. Complicating matters, consonant realization? breathiness is phonetically realized as a breathy- Is consonant breathiness distinguished from voiced aspirated release into the following vowel, vowel breathiness in the degree of realization? so how do speakers distinguish breathiness How do these sounds differ across Gujarati and associated with a consonant release [CʱV] from White Hmong? reathiness associated with a owel [CV ] if at all By comparing these two unrelated languages, The current study investigates acoustic and we hope to discover the articulatory and acoustic articulatory (electroglottographic) properties of similarities and differences in the production of consonantal and vocalic breathiness in ambiguous these sequences. contexts, discovering that speakers of both languages consistently differentiate the two 2. METHODS underlying sequences in the relative timing/ 2.1. Subjects duration and magnitude of the phonetic realization of breathiness. The subjects in the current study are all literate in their native language, either Gujarati or White Keywords: phonation, breathy, Gujarati, White Hmong. All were residents of the US at the time of Hmong, electroglottography recording. Ten speakers of Gujarati (3 male, 7 1. INTRODUCTION female) were recorded in Los Angeles; their ages ranged from 20-50. Twelve speakers of White Contrastive breathy voice is widespread, with Indic Hmong (6 male, 6 female) were recorded in St. languages such as Hindi [16] and Bengali [10] Paul; their ages ranged from 24–58. distinguishing breathy (voiced aspirated) consonants from modal (voiced unaspirated) 2.2. Recording consonants, and Zapotec languages [3][15] For both languages, three types of words were distinguishing breathy vowels from modal vowels. recorded based on their target CV sequence: However, only a small handful of languages use breathy voice contrastively on both consonants and “Breathy V” reath owels [CV ] vowels; these include Gujarati, White Hmong, and “Breathy-asp. C”: breathy consonants [CʱV] Khoisan languages [14] [19]. “Modal”: no breathiness [CV] What makes this small group of languages The Gujarati stimuli consisted of minimal and particularly interesting is that they exhibit CV near-minimal triplets, produced at a natural speech sequences where breathy voice could potentially rate at the beginning of sentences that subjects be associated with the consonant [Cʱ] or with the themselves created (e g [ a ɾ ʈʰəɳɖi ʧʰe] ‘It’s cold vowel [V ] Cr ciall since (stop) consonant o tside ’). This approach was used to minimize the breathiness is realized not during the closure itself known effects of slow, formal, read speech [2]. but as a breathy-aspirated release into the vowel, The White Hmong stimuli consisted of near- how do speakers disting ish [CʱV] (with a reath - minimal triplets, produced in the carrier phrase
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ICPhS XVII Regular Session Hong Kong, 17-21 August 2011
Rov hais X dua [ʈɔ24 hai22 X duə33] ‘Sa X Table 1: Measures that significantly distinguish post- again’. aspirated vowels from breathy and modal vowels (p≤0.001) across five timepoints in Gujarati. 2.3. Measurements Timepoint Breathy Modal T1 (none) H1*–H2*, The measures used in the current study include H1*–A3*, CQ those that have been shown in previous studies of T2 H1*–H2*, H1*–H2*, Gujarati [1], [4],[9], [11] and White Hmong [3] [5] H1*–A3*, H1*–A3*, [9] to be successful at distinguishing breathy and CPP CPP, CQ modal vowels in the two languages. These include T3 H1*–H2*, H1*–H2*, the following: CPP H1*–A3*, CPP, CQ H1*–H2*, the amplitude difference between T4 & T5 (none) H1*–H2*, the first and second harmonics, corrected for H1*–A3*, the effects of adjacent formants [6] [8]. CPP, CQ H1*–A3*, the corrected amplitude difference Table 2: Measures that significantly distinguish post- between the first harmonic and third formant. aspirated vowels from breathy and modal vowels (p≤0.001) across five timepoints in White Hmong. Cepstral peak prominence (CPP), a measure of noise and/or aperiodicity [7]. Timepoint Breathy Modal Closed quotient (CQ), the portion of time the T1 H1*–H2*, H1*–H2*, CPP, CQ, CQ, DECPA glottis is open per pulse, measured using the DECPA hybrid method with a 25% threshold. T2 CPP, CQ H1*–H2*, CQ, Derivative-EGG closure peak amplitude DECPA DECPA (DECPA), the peak positive value for each T3 CPP, CQ, DECPA pulse in the derivative of the EGG signal [13]. DECPA T4 & T5 CPP, CQ, (none) Measurements were taken automatically using DECPA the acoustic and electroglottographic analysis programs VoiceSauce [17] and EggWorks [18], 3.2. Gujarati respectively, at every millisecond of vowel 3.2.1. Acoustic duration and then averaged within nine parts of equal length. Since we assume that the relevant Along spectral measures H1*–H2* and H1*–A3*, distinctions across the phonation categories will be modal, breathy, and post-aspirated vowels in concentrated at the beginning and middle of the Gujarati are all indistinguishable at the consonant owel’s d ration onl the first fi e of these nine release. However, by T3, post-aspirated vowels averages (i.e. the first five “timepoints”, T1–T5) exhibit a significantly higher value than breathy were subjected to statistical analysis. vowels, which exhibit a significantly higher value The following terminology is used in the results than modal vowels. By T5, post-aspirated and to refer to the three categories: breathy vowels are statistically indistinguishable from each other, but both show statistically higher “Breathy” phonemicall reath owel [V ] H1*–H2* and H1*–A3* values than modal “Post-aspirated” V following reath C [ʱV] vowels. H1*–H2* values for all three categories “Modal” no reathiness [V] are shown in Figure 1 below. 3. RESULTS Like the spectral measures, CPP is also unsuccessful at distinguishing categories at the 3.1. Overview onset, and also shows a delayed peak in breathy Results of ANOVAs and post-hoc pair-wise vowels relative to that of post-aspirated vowels. comparisons for each measure at each timepoint However, CPP differs from spectral measures in determined if there was a significant (p ≤ 001) that the values rise across the five timepoints for difference between the three vowel types: breathy, all three categories. Only the steepness of the rise post-aspirated, and modal. The measures that distinguishes them: modal vowels rise in CPP the significantly distinguished post-aspirated vowels fastest, and breathy vowels the slowest, while post- from either breathy or modal vowels are aspirated vowels show an intermediate level. summarized below in Table 1 for Gujarati and in Table 2 for White Hmong.
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Figure 1: H1*–H2* values across T1–T5 in breathy, A3*, however, was not successful at distinguishing post-aspirated, and breathy vowels in Gujarati. Higher any contrasts in White Hmong. values are associated with greater breathiness. Figure 3: H1*–H2* values across T1–T5 in breathy, Post-aspirated Breathy Modal post-aspirated, and breathy vowels in White Hmong. Higher values are associated with greater breathiness. 13
11 Post-aspirated Breathy Modal 0.6 9 0.55 7
CQ 0.5
H1*-H2*in dB 5 0.45 T1 T2 T3 T4 T5 0.4 T1 T2 T3 T4 T5 3.2.2. Electroglottographic Electroglottographic results largely match the In terms of CPP, White Hmong vowels are acoustic patterns. CQ (Figure 2) distinguished divided into two statistically-distinct categories: post-aspirated from modal vowels across all five breathy vowels show a lower value while modal timepoints, but the CQ of breathy vowels showed and post-aspirated vowels are higher and not more dynamic behavior. Breathy vowels started distinguished from each other. out more modal and later merged with the post- 3.3.2. Electroglottographic aspirated category at T3; at no point, however, are post-aspirated vowels statistically distinguished Electroglottographic results indicate that White from breathy vowels by CQ. DECPA did not Hmong vowels can be distinguished by phonation distinguish any two categories at any timepoint. category along both CQ and DECPA parameters. In CQ (Figure 4), post-aspirated vowels start out Figure 2: CQ values across T1–T5 in breathy, post- aspirated, and breathy vowels in Gujarati. Lower with an extremely low CQ, significantly lower (i.e. values are associated with greater breathiness. breathier) than modal or breathy vowels across T1 and T2. However, this quickly changes by T3,
Post-aspirated Breathy Modal where post-aspirated vowels lose their breathiness 0.6 and essentially merge with modal vowels, taking 0.55 on statistically higher CQ than breathy vowels. 0.5 Figure 4: CQ values across T1–T5 in breathy, post- CQ 0.45 aspirated, and breathy vowels in White Hmong. 0.4 Lower values are associated with greater breathiness. 0.35 Post-aspirated Breathy Modal T1 T2 T3 T4 T5 0.6 0.55 3.3. White Hmong
3.3.1. Acoustic CQ 0.5 White Hmong post-aspirated vowels start out at T1 0.45 with an H1*–H2* value (Figure 3) significantly 0.4 higher than that of breathy vowels, which have a T1 T2 T3 T4 T5 significantly higher value than that of modal vowels. However, the H1*–H2* of post-aspirated DECPA distinguishes post-aspirated vowels vowels decreases and essentially merges with the from breathy vowels from T1 through T3, with modal category by T3, and becomes statistically post-aspirated vowels exhibiting the highest distinct from post-aspirated vowels by T5, where values. Then, this category loses breathiness and the latter category increases in breathiness. H1*– becomes statistically distinct from breathy vowels
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ICPhS XVII Regular Session Hong Kong, 17-21 August 2011
at T4, while it remains statistically separate from both languages, along multiple acoustic and the modal category through T5. articulatory/electroglottographic parameters. Naturally, language-specific differences were 4. DISCUSSION found, and the next logical step in this research is a Speakers of both Gujarati and White Hmong perception study, ideally also including Khoisan distinguished consonantal and vocalic breathiness languages (the only other reported languages with by the timing/duration of the realization of breathy breathy vowels and consonants) for a stronger voice. The realization of consonantal breathiness typological perspective. Given the cross-linguistic was concentrated within the onset of the vowel, similarities, will listeners be able to correctly while vocalic breathiness was produced more associate breathy voice with consonants and evenly across the first half of the vowel. This short, vowels, or will language-specific biases prove early realization of breathiness in post-aspirated stronger? Such a follow-up will help further reveal vowels presumably indicates that it is associated characteristics of this very rare phenomenon. with the preceding stop and not with the vowel. 6. REFERENCES Arguably more surprising was the consistent distinction in the relative magnitude of breathy [1] Bickley, C. 1982. Acoustic analysis and perception of voice. In both languages, consonantal breathiness breathy vowels. MIT Speech Communication Group WP. [2] Dave, R. 1967. A formant analysis of the clear, nasalized, was realized with a more extreme production than and murmured vowels in Gujarati. Indian Ling 28, 1-30. vocalic breathiness. We hypothesize that this [3] Esposito, C.M. 2010. Variation in contrastive phonation amplification of consonantal breathiness serves to in Santa Ana del Valle Zapotec. JIPA 40(2), 181-198. compensate for its aforementioned short duration, [4] Fischer-Jørgensen, E. 1967. Phonetic analysis of breathy thus ensuring its salience to the hearer. (murmured) vowels. Indian Ling 28, 71-139. [5] Fulop, S., Golston, C. 2008. Breathy and whispery Besides the cross-linguistic similarities, there voicing in White Hmong. Proc. of Mtgs. on Acoustics 4. are language-specific properties. Some involve the [6] Hanson, H.M. 1995. Glottal characteristics of female success of measures, e.g. H1*–A3* distinguishes speakers. Ph.D. dissertation, Harvard University. categories only in Gujarati while DECPA is useful [7] Hillenbrand, J.M., Cleveland, R.A., Erickson, R.L. 1994. Acoustic correlates of breathy vocal quality. JSHR 37. only in White Hmong. Other differences include [8] Iseli, M., Shue, Y.-L., Alwan, A. 2007. Age, sex, and the shorter duration of post-aspirated breathiness in vowel dependencies of acoustic measures related to the White Hmong and the fact that Gujarati post- voice source. JASA 121, 2283-2295. aspirated vowels more closely resemble breathy [9] Keating, P., Esposito, C.M., Garellek, M., Khan, S.D., vowels along more measures at more timepoints, Kuang, J.J. 2010. Phonation contrasts across languages. UCLA Working Papers in Phonetics 108. while in White Hmong, they more closely [10] Khan, S.D. 2010. Bengali (Bangladeshi Standard). JIPA resemble modal vowels. These factors suggest that 40(2), 221-225. non-native listeners would more likely group post- [11] Khan, S.D. Unpublished. The Phonetics of Contrastive aspirated vowels with breathy vowels in Gujarati Phonation in Gujarati. [12] Kreiman, J., Gerratt, B.R., Khan, S.D. 2010. Effects of and with modal vowels in White Hmong. native language on perception of voice quality. J. Phon 38. 5. CONCLUSION [13] Michaud, A. 2004. A measurement from EGG: DECPA, Gujarati and White Hmong are exceptional in that and its application in prosody. Proc. of Speech Prosody. [14] Miller, A.L. 2007. Guttural vowels and guttural co- both languages have independently generated a artic lation in J |’hoansi J. Phon 35, 56-84. contrast between breathy consonants and breathy [15] Munro, P., Lopez, F. 1999. Di’syonaary X:tee’n Diizh vowels, a phonological opposition not even seen in Sah Sann Lu’uc. Los Angeles: Chicano Stud.Res.Ctr.Pub. their closest relatives (e.g. Hindi, Green Mong). [16] Ohala, M. 1983. Aspects of Hindi Phonology. Delhi: Motilal Banarsidass. What is particularly striking is how speakers of [17] Shue, Y.-L., Keating, P., Vicenik, C. 2009. VoiceSauce: these unrelated languages consistently maintain A program for voice analysis. JASA 124(4), 2221. this distinction in a very similar way: breathy [18] Tehrani, H. 2009. EGGWorks: a program for automated consonants exhibit a short period of magnified analysis of EGG signals. breathiness in the following vowel, while breathy http://www.linguistics.ucla.edu/faciliti/facilities/physiolo gy/egg.htm vowels are characterized by subtler cues of [19] Traill, A. 1985. Phonetic and Phonological Studies of breathiness distributed across a longer duration. !Xóõ Bushman. Hamburg: Helmut Buske. These realizations of breathiness are evident in
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