The nasal vowels in Maithili: an acoustic study*

Journal of Phonetics (1986) 14, 223- 230

The nasal vowels in Maithili: an acoustic study* Sunil Kumar Jha Tribhuvan University, S.M.B.M. Campus, Rajbiraj, Saptari, Nepal Received 16th July 1985, and in revised form 6th January 1986

Maithili is a modern Indo-Aryan language spoken by a total of about 21 million people in the eastern and northern regions of the state of Bihar in India and in the Tarai districts of Nepal. This language has eight phonologically distinctive oral vowels /i e re a ;) 3 o uj as well as eight phonologically distinctive nasal vowels ;T e ie a :i 3 o u/. This paper attempts to present a description of the main acoustic realisations of these nasal vowels.

1. Introduction

The use of a certain phonetic dimension in a given language may or may not reflect a corresponding contrast in the phonology of that language. Vowel nasalization, for example, is a phonetic phenomenon which does not reflect a phonological contrast in, say, English, although this phonetic phenomenon is often present to some extent whenever a derived level non-nasal vowel occurs between nasal consonants. However, there are languages, e.g. French, Portuguese, Gujarati, Hindi and Maithili, in which vowel nasalization does not mark a phonological contrast. Various studies on vowel nasalization (e.g. Lightner, 1970; Ruhlen, 1973; Ferguson, 1974; Cagliari, 1977) point out that many languages show long phonetic vowels in place of underlying vowel plus nasal (VN) sequences. As in Hindi and Urdu (e.g. Narang & Becker, 1971; Bhatia & Kenstowicz, 1972), and also Gujarati (e.g. Dave, 1977), Maithili has phonologically distinctive nasal vowels. The present author is a native speaker of a variety of the " standard" dialects ofMaithili, and with this article he aims to analyse the main acoustic realizations of the nasal vowels of that dialect, basing his study entirely on his own pronunciation. 2. Procedure For the purpose of the present study, a list of test utterances containing the Maithili nasal vowels was prepared, keeping the vowels both in isolation and in word contexts. It should be mentioned here that most of the Maithili vowels in isolation are used as morphemes, and in principle each one of them can be used as a "free" or "bound" *This paper forms part of the fourth chapter of Jha's (1984) doctoral dissertation . The author is grateful to both Professor Marcel A. A. Tatham and Dr Jacques Durand of the Department of Language and Linguistics at Essex University (U.K.) for their detailed criticisms, comments and suggestions on various versions of this study which have led to its improvements both in style and in content. 0095-4470/86/020223

+ 08 $03.00/0

© 1986 Academic Press Inc. (London) Ltd.

224

S. K. Jha

TABLE I. Test utterances containing the Maithili nasal vowels spoken in isolation and in words Vowels in isolation

Vowels in words

Oral and nasal vowels contrasted in words

;I;

/chit/ "garment dyed with spots"

fef

jchet/ " surplus (e.g. of grain)''

;a:;

jsii:j "husband, lover"

;a.;

/has; "goose"

/fl/

/hfls/ " laugh (imp.)"

/3/

js5j "from"

/of

!Qhorh/ "a kind of snake"

/uf

!Qhurh/ "search (imp.)"

jch it/ "scatter" /chit/ "garment dyed with spots" /bhet/ "see"; "get in touch" /bhet/ "a kind of flowerseed" j bh ret/ " will become" j bhii:tj " kind", "type" /bas/ "shelter" /bas/ "bamboo" /'katgar/ " commendable" /'kfltgar/ "thorny" /g:Jt/ "will sing" jg5tj "(cattle) urine" jghotf "mix (imp.)" jghotf "swallow (imp.)" fka ' huf "please say" /ka ' hu/ "somewhere", "in case"

morpheme in this language. All the test utterances used in this study are listed in Table I. Each test utterance was put in a sentence context (the frame of the sentence being ['phero ... bhi'yau] 'please say . .. again') and was spoken at a normal conversational speed. Nine tokens of each test utterance were recorded in a soundproof studio at Essex University. These recordings were made on a Revox B 77 tape-recorder. Of the nine tokens of each test utterance, the first two as well as the last two tokens were ignored, and the remaining five tokens from the middle were used to obtain visual records in the form of spectrograms. Wide band spectrograms and wide band "sections" (i .e. shortterm spectra) of each of the give tokens were made on a Sona-Graph 6061-B Sound Spectrograph. The formant frequency of each token was measured from wideband spectrograms, since these were found to offer the most convenient way of locating the centre frequency of each formant. Duration measurements were made from all the five tokens of each test utterance as recorded in various contexts. Formant frequency and duration measurements were made to the nearest 20Hz and 5 ms, respectively. 3. Results and discussion

3.1. Formant frequency measurement

The phonetic evidence gathered from the spectrograms of the recordings strengthens the fact that each nasal vowel in Maithili is one single speech sound, and not a sequence of an oral vowel plus a nasal consonant. The acoustic analysis presented is based on this observation. Table II presents the average frequencies of the first three formants as well as of the nasal formant (F 0 ) for the nasal vowels spoken in isolation.t Table III lists the average freq uencies of F 1 , F 2 , F 3 and F" for these nasal vowels spoken in words. In 'See Jha (1984, pp. 92, 318- 324) for the detailed frequency values of all the measurements in this and subsequent tables. From Table II onwards, values less than 0.50% are ignored, while those between 0.50 and 0.99% are regarded as I%, i.e. the values are rounded up.

225

Nasal vowels in Maithili II. Average frequency values (Hz) of F 1 , F 2 , F 3 and F 0 for the Maithili nasal vowels spoken in isolation

TABLE

Vowel

!I!

/"e/ /ref fa/ /?!/ /3/ /6/ fuf

F,

Fz

F)

Fn

288 448 708 718 514 580 432 322

2636 2354 1752 1256 1068 856 726 614

3236 3104 2682 2682 2778 2536 2792 2786

962 1274 1084 1534 1178 1336 1140 1070

Fig. 1 a comparison is made between the average F,, F 2 and F 3 frequency values of these nasal vowels and those of their oral counterparts as spoken in isolation. As Tables II and III, as well as Fig. I, show, each nasal vowel in Maithili is distinguished by the first two formants. Whether spoken in isolation or in words, the F 2 for all nasal vowels goes downwards throughout the series: (I e re ;;\ 3 o iij. The F, goes up for the front vowels /1e ref, and then down for the back vowels /3 6 ii/ in that order. The F 1 for fa:/ whether spoken in isolation or in words, always remains higher than that for j;ij. The average F, and F 2 frequencies for these nasal vowels as given in Tables II and III are also plotted on a formant chart in Fig. 2 for a comparison between these vowels spoken both in isolation and in words. In Fig. 2, the actual frequency values shown by broken lines differ from those shown by unbroken lines, in that the former display the effects of the consonantal environments in which the nasal vowels were spoken . 4000,---------------------------------------. 300 0- __Ff... _ 2000N

I

1000----

- ~' --

_ ..5_ _ _

0

>

>-

<.)

c: Q)

:::>

rr

~

4000,---------------------------------------,

Q)

c>

2Q) >

<[

F1

F,~~~=

.,.

oL-------------~----~--------~r~,,-==-====-~ ;,;; lool luul I~ ~I

Figure I. A comparison between the average frequency values of F 1 , F 2 and F 3 for the Maithili oral vowels(-) and for their nasal counterparts(---) spoken in isolation.

226

S. K. Jha

III. Average frequency values (Hz) ofF 1 , F 2, F 3 and F" for the Maithili nasal vowels spoken in words

TABLE

Vowel

Word

ill

/chit/ /chet/

fef /ref fa/ /3/ /3/

/5/ Iii/

fsre/ /has/ /h3s/ fs3/

/Qhorh 1 /Qh urh I

FI

F2

FJ

Fn

330 436 750 736 534 610 442 338

2638 1944 1728 1294 1246 894 770 634

3490 2608 2598 2480 2542 2576 2764 2566

952 1068 1126 974 1722 1486 1484 1092

Figure 2 clearly shows that, except for jej , the nasal vowels, ;Ire a ~ 3 5 fi/, maintain relatively lower vowel heights when spoken in words rather than in isolation. In addition, when spoken in words (i) the front nasal vowels /e ref becomes less fronted; (ii) the central nasal vowels fa ~/ become more central, i.e. more fronted; and (iii) the back nasal vowels /3 5 fi/ become less back. Figure 3 illustrates the oral and the nasal vowels in Maithili spoken in isolation. The figure demonstrates a good deal of similarity between the overall frequency patterns of these oral and nasal vowels. It also shows that the nasal vowels maintain relatively lower vowel heights than their oral counterparts. In addition, Fig. 3 shows that, when compared with their oral counterparts: (i) the front nasal vowels ;I e ref are more fronted; (ii) the central nasal vowels fa ~/ become less central, i.e. less fronted; and (iii) the back nasal vowels /3 5 fi/ become more back. In order to make a further comparison between these oral and nasal vowels, each one was also recorded in words of the same stress and consonantal environments. In this type of comparison, too, the results showed patterns similar to those displayed in Fig. 3. Thus, F2 (Hz) 30 0 0 2600 2200 1800 I

1200 800 1400 1000 I

500

I

300 400 500

g L.L

600 700 L-----------------------~800

Figure 2. Average frequency values of F 1 and F 2 for the Maithili nasal vowels ) and in words (---). spoken both in isolation (-

Nasal vowels in Maithili

227

F 2 (Hz)

3000 2600 2200 1800 I

I

I

1200 800 1400 1000 I

I

I

I

500

300

I

300 400

600 700 L-------------------------~ 800

Figure 3. Average frequency values ofF, and F 2 for the Maithili oral vowels ()and nasal vowels (---) spoken in isolation .

the acoustical measurements displayed in this paper, together with close inspection of formant amplitudes and the relative intensity of the first three formants of all the oral and nasal vowels in Maithili, lead to the following main observations. First, the results support the observations of most previous investigators of nasal vowels (e.g. House & Stevens, 1956, p. 225; Fant, 1960, pp. 148- 149; Kongsdal, 1967, pp. 59-66; Dave, 1977, pp. 62- 68; Yadav, 1979, pp. 173-174) that the major attributes for these vowels lie in the region of F 1 • This study reveals that the major attribute for nasal vowels in the F, region is F 1 frequency. The results ofF, frequency-measurements show that, on average, all the nasal vowels in Maithili maintain relatively higher frequency values, and therefore relatively lower "vowel height", than their oral counterparts. It was also observed that in the nasal vowels, when compared with their oral counterparts, the F, loses much of its intensity in favour of the F 2 . In addition, the F, amplitude for the nasal vowels remains relatively lower than that of their oral counterparts. Second, the results show a good deal of similarity between the overall frequencypatterns of the Maithili oral and nasal vowels. Yet, on the whole, when compared with their oral counterparts, the nasal vowels occupy relatively more extreme positions in the formant charts than the oral vowels. Third, almost all spectrograms investigated in this study show that the relative intensity of F 3 is much weaker in the Maithili nasal vowels than in their oral counterparts. Finally, the appearance of nasal formants has been reported to be an important attribute of nasal vowels (e.g. Joos, 1948; Fant, 1960; Delattre, 1969; Cagliari, 1977; Dave, 1977; Ladefoged, 1982). According to Smith (1951), nasal formants usually occur in nasal vowels at around lOOOHz. The Fn measurements presented in the current study support Smith's claim, but only partly. Although it does not always seem easy to determine the exact Fn frequency of nasal vowels, the results show that the average Fn frequency region for the Maithili nasal vowels has a range between 952 and 1722Hz. This range should not be taken as surprising because Ladefoged ( 1982, p. 173), too, reports the presence of "pseudoformants" for some American English vowels at around 1700Hz "due to a slight degree of nasalization", and Dave (1977, p. 67) also reports the presence of " extra formants" for some Gujarati nasal vowels "in the region of I 000 to 2500cps".

S. K. Jha

228 TABLE

IV. Average duration (ms) of the Maithili nasal vowels Vowel

.,. Spoken in isolation Spoken in words

I

e

re

a

;}

3

6

il

241 160

253 196

270 255

280 227

150 102

275 231

256 211

235 196

300 -;;;

.E ~

::>

'0

.----:-;\ ~~--

. ---

<::

.9

zoor-- i

Ql

• ....-

""(i;0

/ / -----..... ----.

e /

/

\

/ ....-•

\

>

;i;

\

\

<{

100

,

; 3;

.

I

I

•--

............. 0 .............

-•, "-

I

N

u

--.

\ ~ I

v

; ;;

;0;

; ;:; ;

Figure 4. Average duration of the Maithili nasal vowels as spoken in isolation ( - ) and nasal vowels (---) spoken in words of the same stress and consonantal environments.

3.2. Duration measurements

To determine the relative duration of the Maithili nasal vowels, duration measurements of all these vowels were made from spectrograms. Following the experimental method outlined earlier in this paper, the duration of these vowels was measured in ms. Table IV lists the average duration of these nasal vowels spoken in isolation and in words.t The average duration values of these tables are also plotted on a chart as displayed in Fig. 4. The figure clearly shows that the nasal vowels spoken in isolation have longer durations than when spoken in words. It also shows that open nasal vowels tend to maintain longer durations than less open and close ones. The relative durations of the Maithili oral and nasal vowels as spoken in words are also compared. Table V presents the average durations of all these vowels spoken in words of the same stress and consonantal environments. The average duration values for these vowels as given in Table V are also graphically plotted in Fig. 5. As Fig. 5 shows, there is a good deal of similarity between the overall duration patterns of these oral and nasal vowels. In general, even when spoken in words of the same stress and consonantal environments, the nasal vowels remain longer in duration than their oral counterparts-the length of this duration difference ranging between 3 and 7% within the overall utterance. Pathak (1976, p. 314) carried out an electrokymographic study of phonetic nasalization in Bagheli-a dialect of Hindi spoken in eastern India -and came to a similar conclusion: "the nasalized vowels in Bagheli have a little longer duration than their oral counterparts". The present results shown in Table V and I See Jha (1984, pp. 325- 326) for the detailed duration measurement values for each of the total recorded tokens, from which only the averages are given in Tables IV and V.

229

Nasal vowels in Maithili

V. Average duration of the Maithili oral and nasal vowels spoken in words of the same stress and consonantal environments, together with the average duration of overall utterance and the average percentage of vowel duration within the overall utterance

TABLE

Vowel

Word

Vowel duration (ms)

Duration of overall utterance (ms)

Percentage of vowel duration withi n the overall utterance

ill

/i/

;chit/ /ch'lt;

132 160

278 310

47 51

je/ /e/

/bhet/ /bhet/

159 202

306 342

52 59

/C£/ /re/

/bh C£t/ /bh ret/

197 231

419 455

47 51

/a/ /a/

/bas/ /bas/

218 247

424 448

51 55

/;}/ /3/

/'btg';Jr/ /'k3tg';Jr/

59 80

436 449

14 18

/'J/ /3/

/g'Jt/ /g3t/

22 1 260

411 428

54 61

/o/

/ghot/ /ghat/

207 242

404 438

51 55

/b'hu/ /b'hil/

326 352

440 456

77

/6/ /u/

/ill

74

350 300

v;

../ . ./e

__s

e

c:: .Q

/

~:J

';'

/

l

"0
"'

"'


/

;; ,;

~·-

~·\

. ~.· ' \ "'

\

\

>
•• 0

I i Tl

I

ee

I l"':illaal

I • ;I

I~

;I

I o

oI

I u

uI

Figure 5. Average duration of the Maithi li oral vowels () and nasal vowels (---)spoken in words of the same stress and consonantal environments.

Fig. 5 indicate quite clearly that the presence of the nasal vowel lengthens the overall utterance. That is to say, in almost each test utterance of Table V there is no compensation for the increased length of the nasal vowel taking place elsewhere in the utterance. And, in general, these data also confirm that, other things being equal, in Maithili open vowels remain longer in duration than close vowels.

230

S. K. Jha References

Bhatia, T. K . & Kenstowicz, M. J. (1972). Nasalization in Hindi: a reconsideration , Papers in Linguistics, 5, 202- 215. Cagliari, L. C. (1977). An Experimental Study of Nasality with Particular Reference to Brazilian Portuguese. Unpublished Ph.D. thesis, University of Edinburgh, U .K. Dave, R. (1977). Studies in Gujarati Phonology and Phonetics. Unpublished Ph.D. thesis, Cornell University, U .S.A. Delattre, P. (1969). Explaining the chronology of nasal vowels by acoustic and radiographic analysis. In The General Phonetic Characteristics of Languages, pp. 101 - 119. U.S. Department of Health, Education and Welfare, Office of Education, Institute of International Studies. Fant, G. (1960). Acoustic Theory of Speech Production. The Hague: Mouton and Co. Ferguson, C. A. (1974). Universals of nasality, Stanford University Working Papers on Language Universals, 14, 1- 16. House, A. S. & Stevens, K. N. (1956). Analog studies of the nasalization of vowels, Journal of Speech and Hearing Disorders, 21 , 218- 232. Jha, S. K . (1984). A Study of Some Phonetic and Phonological Aspects of Maithili. Unpublished Ph.D . thesis, University of Essex, U.K. Joos, M. (1948) . Acoustic Phonetics . Baltimore: Linguistic Society of America, Waverly Press. Kongsdal , J. 0. (1967). Features of the acoustical and physiological structure of the French nasal vowels, Annual Report of the Institute of Phonetics (University of Copenhagen), I, 59-66. Ladefoged, P. (1982). A Course in Phonetics, 2nd Edition. New York: Harcourt Brace Jovanovich. Lightner, T. M. (1970). Why and how does vowel nasalization take place? Papers in Linguistics, 2, 179- 226. Narang, G . C. & Becker, D. A. (1971) . Aspiration and nasalization in the generative phonology of Hindi- Urdu, Language, 47, 646-667. Pathak, R. S. (1976). Nasalization in Bagheli: an electrokymographic study, Indian Linguistics, 37, 312- 315 . Ruhlen, M. (1973). Nasal vowels, Stanford University Working Papers on Language Universals, 12, 1- 36. Smith, S. (1951). Vocalization and added nasal resonance, Folia Phoniatrica, 3, 65-69. Yadav, R . (1979). Maithili Phonetics, and Phonology. Unpublished Ph.D. thesis, University of Kansas, U.S.A.