Band 37, Heft 5-6

This paper reports the results of a study in which variability of formant frequencies for different vowels was examined with regard to several predictions derived from the quantal theory of speech. Two subjects were required to reproduce eight different steady-state synthetic vowels which were presented repeatedly in a randomized order. Spectral analysis was carried out on the vocal responses in order to obtain means and standard deviations of the vowel formant frequencies. In the spirit of the quantal theory, it was predicted that the points vowel. /i/, /a/ and /u/ would show lower standard deviations than the nonpoint vowels because these vowels are assumed to be produced at places in the vocal tract where small perturbations in articulation produce only minimal changes in the resulting formant frequencies. That is, these vowels are assumed to be quantal vowels. The results of this study provided little support for the hypothesis under consideration. A discussion of the outcome of the results as well as some speculation as to its failure to find support for the quantal theory is provided in the report. Several final comments are also offered about computer simulation studies of speech production and the need for additional empirical studies on vowel production with real talkers.

An experiment was conducted to examine whether a bite block affects the latency and/or the quality of spoken vowels. The results suggest that vowels spoken with the bite block and vowels spoken normally were (1) of the same latency, that is, the same time elapsed between visual presentation and initiation of response; and (2) of the same quality, that is, the acoustic measures of the vowels did not differ substantially. Moreover, there was minimal evidence of improvement in either latency or quality with practice, and minimal evidence of an effect of time pressure on the quality of bite-block vowels. A detailed consideration is given to the implications of these and other findings for two recent perspectives on vowel production.

Evidence is accumulating that native speaker-hearers are not as consistent, confident, or in agreement, on counting the number of syllables in natural utterances as is commonly assumed. There are, however, instances where speaker-hearers give clear, consistent syllable counts. It is the position of this paper that the unclear cases as well as the clear cases are phonetically classifiable in terms of sonority. The experiments presented here are intended to delimit what is meant by sonority in acoustic terms.

Data from esophageal speech produced by laryngectomized patients was used to provide a reexamination of major contemporary hypotheses advanced to account for intrinsic variation in vowel fundamental frequency (F₀). 4 speakers provided recordings of 15 tokens of three CVC syllables [hid, hud, had]. Analysis of these utterances revealed that intrinsic variation in vowel F₀ is clearly evident in esophageal speech. These findings were interpreted (1) to support neither the source-tract coupling nor the tongue-pull hypotheses and (2) to highlight the need to test alternative explanations to account for the intrinsic variation in vowel F₀.

During dichotic stimulation with CV [stop + vowel] syllables, 5 subjects reported right ear (RE) targets as the left ear (LE) mask syllable lagged behind RE by 0–200 ms. Seven-step synthetic speech continua for voice (/pa-ba/, /ta-da/) and place (/pa-ta/, /ba-da/) served as stimuli; stimulus 1 and 7 were phonetically ‘optimum’ allophones for the four above-mentioned phoneme contrasts. RE targets were always stimulus 1 or 7 of any given continuum, and masks were all seven allophones of the same continuum. Results showed interference only when target and mask were differing phonemes; as mask stimuli were increasingly further from the phoneme boundary separating them from the target, interference increased in amount and temporal extent, such that stimulus 1–7 pairs showed most interference. Voiceless and alveolar masks were more potent than voiced or labial masks. Results suggest that allophonic information for stops perists and is effective in dichotic interference at a very high level of the phonemic labeling process. The data support models of perception which invoke simultaneous, in-depth allophonic as well as phonemic processing of speech segments.

34 children (average age 3; 3) furnished perception and production data on five initial voiced-voiceless stop cognates. In addition to the usual systematic effects of place of articulation, significant individual differences were found in both mean produced values of voice onset time (VOT) and mean perceptual boundary in terms of VOT. There was a suggestion of within-sample cross-sectional age trends in both production and perception data. Some restricted correlations between the two types of data were observed and were interpreted as indicating an earlier development of perceptual cue usage than of articulatory control, possibly causative. The restriction appeared to be related to the very low variance in the perception measures. Consideration of average discrepancies between mean perception and mean production data suggested that interpretation of trends in production data may be assisted by taking a measure of the point of overlap between voiced and voiceless productions, rather than the simple average of their means.

Simultaneous recordings of voice and cricothyroid activity during speech gestures by one speaker of Hindi were made. The experimental utterances consisted of monosyllabic and bisyllabic meaningful and nonsense words containing in prestressed initial and medial and poststressed final positions the voiced and unvoiced stops and affricates from both the aspirated and unaspirated categories. All of the words were embedded in the carrier sentence ‘baba – ap boliye’. The results show markedly higher levels of cricothyroid activity for the unvoiced stops and affricates than for their voiced cognates. This cricothyroid activity appears to facilitate voicelessness through increased fold tension during unvoiced stops and affricates and thus contributes to the execution of voicing distinction in voiced and unvoiced stops and affricates. Fundamental frequency data obtained on precisely the utterances reported in this paper also seem to fit the hypothesis that unvoiced stops and affricates have higher fold tension than voiced stops and affricates.