Variations In Voice Onset Time Research Articles

Convergence to shortened and lengthened voice onset time in an imitation task.

Convergence to variation in voice onset time (VOT) of English voiceless stops is reported to be selective, with speakers adjusting their VOTs after exposure to stimuli with lengthened, but not shortened, VOT. The current study re-examined this proposed selectivity with an explicit imitation paradigm designed to maximize convergence, using stimuli with more extreme differences, and explored the perceptual salience of the differences in a discrimination task. Participants showed phonetic convergence to both shortened and lengthened VOT, and better discrimination of shortened than lengthened VOT. Results suggest that there is no general constraint against convergence to shortened VOT.

From interference to transfer in language contact: Variation in voice onset time

AbstractThis study examines cross-generational differences in the realization of an English phonological contrast by bilingual Polish Americans in New York City. I analyze the production of voice onset time (VOT) in underlying stops, as intinandden, and stops derived from interdental fricatives, as in [t]in forthinand [d]en forthen, in an English-only reading task. Generation one exhibits VOT “interference” for both stop types, with a bias toward interference for voiced stops. Generation two “transfers” Polish-like VOTs to derived stops. I argue that the cross-generational progression from theglobaleffects of interference to thefocusedpresence of transfer is filtered through L1 markedness and reflects speakers' growing sensitivity to L2 phonology and social considerations. The observed asymmetries in the distribution of interference/transfer are unaccountable by existing models of L2 acquisition and motivate a view of L1/L2 phonetic categories as governed by a variable grammar with access to phonological and social information.

Variation in Voice Onset Time in Stops in Gurindji Kriol: Picture Naming and Conversational Speech

Gurindji Kriol is the home language of children and adults under about 40 years of age in the traditionally Gurindji-speaking communities of northern Australia. Nearly all words in Gurindji Kriol are derived from Gurindji or from Kriol, both of which have been described as lacking a stop voicing contrast, at least in basilectal varieties in the case of Kriol. In this study, we describe variation in voice onset time in Gurindji Kriol, in both picture naming and in conversational speech by young Gurindji Kriol speaking women. For picture naming, Australian English comparison data are also reported. The results indicate that in Gurindji Kriol, VOT varies systematically in expected ways by place of articulation, and position in word and utterance, but not according to the phonological voicing category of cognate English words. Initial stops tend to have short-lag VOT of up to 30 ms; values can be longer in English code-switched forms. Medial stops tend to have negative VOT. The present data do not suggest a voicing contrast based on VOT.

Kera tone and voicing interaction

This paper sets out to investigate the relative role of Voice Onset Time (VOT) and fundamental frequency in a language with lexical tone. By comparing English and the Chadic language Kera, this study explores the interaction between the production and perception of voicing and the role played by voicing in the phonological structure of the language. The major finding is that the role of VOT and F0 in the perception of voicing differs dramatically between English and Kera subjects with English subjects relying mainly on VOT and Kera subjects mainly on F0. The phonological implications of these results for Kera are that tone is contrastive while voicing is not, which is the reverse of English. I will propose that Kera has no [voice] feature, and that the variation in VOT plays a role as a supporting cue to tone, although the exact amount of VOT usage in Kera production and perception differs depending on the amount of contact with French. The dominance of tone suggests that despite claims that Kera exhibits long-distance voice spreading, what spreads is in fact tone rather than voice.

Variation in Voice Onset Time of Stops: The Case of Chinese Korean

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Representational specificity of within-category phonetic variation in the long-term mental lexicon.

This study examines the potential encoding in long-term memory of subphonemic, within-category variation in voice onset time (VOT) and the degree to which this encoding of subtle variation is mediated by lexical competition. In 4 long-term repetition-priming experiments, magnitude of priming was examined as a function of variation in VOT in words with voiced counterparts (cape-gape) and without (cow-*gow) and words whose counterparts were high frequency (pest-best) or low frequency (pile-bile). The results showed that within-category variation was indeed encoded in memory and could have demonstrable effects on priming. However, there were also robust effects of prototypical representations on priming. Encoding of within-category variation was also affected by the presence of lexical counterparts and by the frequency of counterparts.

Variation in Voice Onset Time for Korean Stops

Abstract. Acoustic data elicited from 34 native speakers of Korean living in the United States pro-vide evidence for diachronic change in the voice onset time (VOT) of phrase-initial aspirated and lax stop phonemes. While older speakers produce aspirated and lax stops with clearly differentiated average VOT values, many younger speakers appear to have neutralized this difference, producing VOTs for aspirated stops that are substantially shorter than those of older speakers, and comparable to those for corresponding lax stops. The data further indicate that, within each age group, older speakers manifest sex-based differences in VOT while younger speakers do not. Despite this appar-ent shift in VOT values, the acoustic evidence suggests that all speakers in this study, regardless of age, continue to mark underlying differences between aspirated and lax stops in terms of stop closure and the fundamental frequency of the following vowel. It is concluded that the data point to a recent phonetic shift in the language, whereby VOT no longer serves as the primary cue to differentiate between lax and aspirated stops. There is not, however, evidence of any reorganization of the lan-guage as the phonemic level: the language's underlying lax ~ aspirated ~ tense contrasts endure.

Representational specificity of within-category phonetic variation in the mental lexicon

This study examines whether within-category variation in voice onset time (VOT) is encoded in long-term memory and affects subsequent word recognition, and whether these effects are modulated by the degree of lexical discriminability. Four long-term repetition-priming experiments were conducted using words containing word-initial voiceless stops varying in VOT. The magnitude of priming was compared between same and different VOT conditions in words with voiced counterparts (pat/bat) and words without voiced counterparts (cow/*gow), and in words with high-frequency counterparts (clue/glue) and words with low-frequency counterparts (cab/gab). If veridical representations of each episode are preserved in memory, variation in VOT should have demonstrable effects on the magnitude of priming. However, if within-category variation is discarded and form-based representations are abstract, variation in VOT should not mediate priming. Further, if lexical discriminability modulates the degree of encoding of within-category variation, words with counterparts and words with high-frequency counterparts should show larger specificity effects than words without counterparts and words with low-frequency counterparts. Implications of these results for the specificity and abstractness of phonetic representations in long-term memory will be discussed.

Representational specificity of within-category phonetic variation in the mental lexicon

This study examines (1) whether within-category phonetic variation in voice onset time (VOT) is encoded in long-term memory and has consequences for subsequent word recognition and, if so, (2) whether such effects are greater in words with voiced counterparts (pat/bat) than those without (cow/*gow), given that VOT information is more critical for lexical discrimination in the former. Two long-term repetition priming experiments were conducted using words containing word-initial voiceless stops varying in VOT. Reaction times to a lexical decision were compared between the same and different VOT conditions in words with or without voiced counterparts. If veridical representations of each episode are preserved in memory, variation in VOT should have demonstrable effects on the magnitude of priming. However, if within-category variation is discarded and form-based representations are abstract, the variation in VOT should not mediate priming. The implications of these results for the specificity and abstractness of phonetic representations in long-term memory will be discussed.

Average discharge rate representation of voice onset time in the chinchilla auditory nerve.

Responses of chinchilla auditory-nerve fibers to synthesized stop consonants differing in voice onset time (VOT) were obtained. The syllables, heard as /ga/-/ka/ or /da/-/ta/, were similar to those previously used by others in psychophysical experiments with human and with chinchilla subjects. Average discharge rates of neurons tuned to the frequency region near the first formant generally increased at the onset of voicing, for VOTs longer than 20 ms. These rate increases were closely related to spectral amplitude changes associated with the onset of voicing and with the activation of the first formant; as a result, they provided accurate information about VOT. Neurons tuned to frequency regions near the second and third formants did not encode VOT in their average discharge rates. Modulations in the average rates of these neurons reflected spectral variations that were independent of VOT. The results are compared to other measurements of the peripheral encoding of speech sounds and to psychophysical observations suggesting that syllables with large variations in VOT are heard as belonging to one of only two phonemic categories.

The role of spectral cues in discrimination of voice onset time differences.

The influence of spectral cues on discrimination peaks in the region of the phonetic voicing boundary was examined. The discriminability of voice onset time (VOT) differences of the same temporal magnitude was assessed using stimuli from labial and velar consonant-vowel VOT continua that differed in the timing of spectral changes associated with the first formant (F1) transition, and in the location of the phonetic boundary. Subjects were initially given labeling tests and fixed-standard AX and all-step discrimination tests on both series. Half the subjects then received all-step discrimination training on one series and half received training on the other series. Finally, all subjects were again given the labeling and discrimination tests on both series. Just noticeable differences (jnds) in VOT were estimated from the all-step functions before and after training. Initial jnds showed that VOT discrimination was most accurate around the voicing boundary on the two continua, where differences in F1 onset frequency accompany variations in VOT. jnds on both series decreased significantly after training, although these regions of greater sensitivity remained. No evidence was seen of increased sensitivity around +/- 20-ms VOT, as expected if auditory processing constraints were influencing temporal order judgments. Comparisons of post-training jnds within and across series indicated that spectral components of VOT, primarily F1 onset frequency differences, exert a substantial influence on discrimination, and, along with other spectral cues provided by source differences at stimulus onset, can account for the discontinuities in discrimination often reported in research with VOT continua. Large phonetic effects also were seen in the initial performance of all subjects: jnds decreased consistently as standards drew nearer the voicing boundary. However, these effects were absent in the final jnds for most subjects. Implications of these findings for the understanding of basic auditory and attentional processes in speech perception are discussed.

Perceptual scale for voice onset time (VOT) in synthetic /bae/ /pae/ syllables

The scale used by the perceptual system to represent variations in VOT appears to be different from the physical VOT scale. The perceptual scale, ranging from voiced to voiceless, has zero point at the phonetic boundary (the zero voiced‐voiceless point). The degree of voicedness (voicelessness) increases with the distance between the VOT value and the boundary. Further, the perceptual effect of a difference in VOT near the boundary is greater than at points remote from the boundary. A rescaling of the VOT continuum that is more consistent with the properties of the perceptual scale is given by the function Dxi = k |xi − xb |β,0 < β < 1, where xi is a VOT stimulus value, xB the boundary VOT, k a constant, and Dxi the perceptual magnitude of xi along the voiced (voiceless) scale. The perceptual distance, Δ D, between two stimuli xi,xi + 1, is given by the difference between Dxi and Dxi + 1; that is, Δ D = k ‖xi + 1 − xB|β − |xi − xB|β|. The power transformation at the perceptual level is suggested by the following: (1) the relation between cumulative disciminability and cumulative distance from the boundary, in log‐log coordinates, is well described by straight lines with positive slopes smaller than one. This is observed in /bae/ /pae/ discrimination data obtained in the present and in previous studies [Elman, J. Acoust. Soc. Am. 65, 190–207 (1979)]; (2) for a constant msec difference between xi and xi + 1 the function Δ D reaches a maximum when the pair straddles the boundary, and decreases monotonically as the distance between the stimuli and the boundary increases; (3) changes in discriminability associated with changes in the size of the VOT steps Of the /bae/ /pae/ correlate strongly with changes in Δ D.

Stimulus dominance and ear dominance in the perception of dichotic voicing contrasts

Two studies were conducted to determine the effect of variations in voice onset time (VOT) on the perception of dichotic stop-consonant-vowel syllables contrasting in the voicing feature. The dichotic stimuli were partially fused, so that only a single response was required. Variations in VOT had a systematic effect on the probability of hearing the fused stimuli as voiced or voiceless. Changing the VOT of a voiceless stimulus had a larger effect than changing the VOT of a voiced stimulus. Unless one of the competing stimuli was close to the category boundary, the perceptual integration of their VOTs seemed to be roughly additive. The relative phase of the periodic portions of the stimuli had an unexpected effect on perception that remains to be explained. A number of subjects showed very strong right-ear dominance in these tests. The range and reliability of the laterality effects obtained, as well as certain other methodological features, make the present tests promising as tools for assessing individual differences in ear dominance.

Discriminability, response bias, and phoneme categories in discrimination of voice onset time

The ’’phoneme-boundary effect’’ refers to the observation that discrimination of stop consonants across a boundary between phoneme categories is superior to discrimination of comparable stimulus differences within a phoneme category. The present experiment employed signal detection methodology (a) to distinguish between changes in discriminability and response bias; and (b) to reevaluate the role of phonetic categorization in the phoneme-boundary effect. A SAME–DIFFERENT discrimination task compared discrimination of 10− and 20−msec differences in voice onset time (VOT) in a synthetic stimulus continuum ranging from [ba] to [pa] (VOT’s from −50 to +70 msec). Both a clear increase in discriminability and a marked shift in response bias from SAME to DIFFERENT occurred near the voiced–voiceless boundary. When variations in VOT were isolated from syllable context so that they were not categorized as phonemes, discriminability increased near the voiced–voiceless boundary in a manner comparable to the full-syllable stimuli. These data suggest that the phoneme-boundary effect in VOT discrimination reflects a genuine increase in discriminability near the phoneme boundary. However, in agreement with the recent data of J. D. Miller and his colleagues, these results suggest further that the phoneme-boundary effect for VOT is not due exclusively to phonetic categorization but may instead reflect acoustic and auditory properties which are distinct from phonetic processing. Subject Classification: [43]70.30; [43]65.75; [43]70.35..

Voice onset time, frication, and aspiration in word-initial consonant clusters.

The voice onset time (VOT) and the duration of the burst of frication noise at the release of a plosive consonant were measured from spectrograms of word-initial consonant clusters. Mean data from three speakers reading English words in a sentence frame indicated that the VOT changed as a function of the place of articulation of the plosive and as a function of the identity of the following vowel or sonorant consonant. Burst durations varied in a similar way such that the remaining interval of aspiration in /p, t, k/ was nearly the same duration in comparable phonetic environments. The VOT was longer before sonorants and high vowels than before mid- and low vowels. Aspiration was also seen in an /s/-sonorant cluster. To explain these regularities, production strategies and perceptual cues to a voicing decision for English plosives are considered. Variations in VOT are explained in terms of articulatory mechanisms, perceptual constraints, and phonological rules. Some VOT data obtained from a connected discourse were also analyzed and organized into a set of rules for predicting voice onset time in any sentence context.

Discriminability, response bias, and phoneme categories in voice‐onset‐time discrimination

Considerable theoretical importance has been attached to the “phoneme boundary effect,” in which discrimination across a boundary between phoneme categories is superior to discrimination of comparable stimulus differences with a phoneme category. In order to asses the relative contribution of increases in discriminability and changes in response bias to the phoneme boundary effect, a “same‐different” task compared discrimination of 300‐msec synthetic syllables varying in voice‐onset time (VOT) from −50 to 70 msec. Both a marked increase in discriminability and an equally marked shift in response bias toward “different” responses occurred at VOT values near the phoneme boundary. A second experiment investigated the role of phonetic categorization per se in the phoneme boundary effect. Variations in VOT were isolated from syllable context by eliminating the final 180 msec of steady‐state vowel information from each stimulus. An increase in discriminability comparable to that of the first experiment was obtained for isolated VOT values corresponding to the phoneme boundary. Together with the recent data of Miller et al. [J. Acoust. Soc. Am. 55, 390 (1974)], these results suggest that the phoneme boundary effect for VOT does not depend exclusively upon phonetic categorization but may reflect a more general property of auditory temporal sensitivity.

Variations in VOT for English initial stops

The duration of voice onset time (VOT), using a pause adjustment device, was systematically altered for English stops. For voiceless stops VOT was reduced to half the distance between the voiced and voiceless cognates, VOT was made equivalent to the voiced cognate, and the vocalic portion preceded the release and aspiration segments by 20 ms. Changes in VOT for the voiced stops involved the inversion of the first two measurements described above. In general, our findings did not indicate that changes in VOT duration for stop-vowel syllables altered appreciably the perception of voicing. Further, in a subsequent experiment when only the burst + the first 10, 20 or 30 ms of aspiration were presented to listeners, the stops were identified as voiceless. The conclusions drawn from these experiments are that aspiration is the primary perceptual cue in the detection of voicing, and that VOT operates as a relatively unimportant secondary cue.