English Voice Onset Time Research Articles

Phonetic imitation of a reduced voice onset time on word-initial voiceless stops by native English speakers

This paper investigated whether native English speakers with exposure to a true voicing language (Spanish) would imitate a reduced voice onset time (VOT) on word-initial voiceless stops in English. Nielsen (2011) indicates native English speakers will not imitate a reduced VOT on word-initial voiceless stops since it is approaching the phonological boundary with voiced stops. However, there have been several studies that have found imitation toward a phonological boundary (Mitterer and Enertus 2008, Podlipsky and Simackova 2015). There were nine Native English speakers, some with Spanish language exposure. They completed an imitation study with word initial /p/ and /k/ words with a reduced and enhanced VOT in English. Results indicate that those with and without Spanish exposure do imitate a reduced VOT on word initial voiceless stops in English. The results from the English speakers without Spanish exposure conflict with previous studies that found that native English speakers will not imitate a reduced VOT on word initial voiceless stops to preserve the phonological boundary with voiced stops. The results indicate that native English speakers, whether they have exposure to a true voicing language or not, will approach the phonological boundary with voiced stops in a VOT imitation task.

Analyzing acoustic data with Bayesian finite mixture models: A practical introduction

Acoustic correlates of speech can present empirical distributions that create issues for the linear models we often use to analyze them. In some such cases, we have reason to believe that there are multiple distributions responsible for producing the data. One example is the distribution of voice onset time (VOT) in the phonologically voiced stop series /b,d,g/ in North American English. While more often produced as a short lag stop with a VOT near zero, it can also be produced with prevoicing. This leads to a bimodal distribution of VOT values for these segments. The first study of VOT by Lisker and Abramson (1964) wisely decided to report descriptive statistics for each of these pronunciation variants separately, recognizing that listing a single mean and range would have been a poor characterization of the data and potentially misleading to readers. This tutorial introduces Bayesian finite mixture models, which can model a dependent variable using a combination of two or more distributions. This is useful in situations like the one described above for English VOT, as having two distributions allows us to model both short-lag and prevoiced VOT values together in the same model. The tutorial begins with a brief conceptual explanation of these models, followed by a walkthrough of an analysis of simulated English VOT data using the package “brms” (Bürkner, 2017). An emphasis is placed on setting priors, especially setting informative priors for the intercepts of the two distributions.

Factors affecting voice onset time in English stops

Abstract This study investigates the voice onset time (VOT) of L2 English stops produced by native speakers of Chinese at different L2 proficiency levels. Four factors were examined: English proficiency, gender, place of articulation, and vowel context. High and low achievers of English were recruited as the experimental groups and native speakers of English as the control group. Each group consisted of 16 participants, 8 males and 8 females. Each participant took part in a read-aloud task, in which the target words were presented in an embedded sentence. The results showed that the effects of L2 proficiency were significant in that high achievers outperformed low achievers who were affected by L1 negative transfer more seriously when producing native-like English stops. Additionally, when producing English stops, velar stops had significantly greater VOT values than either bilabial or alveolar ones. However, no significant gender differences were found. Male and female participants produced similar VOT values in English stops. Last, the vowel context was also a significant factor. The VOT lengths differed according to the context of a following vowels. More specifically, the VOT of a stop is significantly longer when followed by a tense vowel.

Voice onset time in English and Korean stops with respect to a sound change*

Voice onset time (VOT) is known to be a primary acoustic cue that differentiates voiced from voiceless stops in the world’s languages. While much attention has been given to the sound change of Korean stops, little attention has been given to that of English stops. This study examines VOT of stop consonants as produced by English speakers in comparison to Korean speakers to see whether there is any VOT change for English stops and how the effects of stop, place, gender, and individual on VOT differ cross-linguistically. A total of 24 native speakers (11 Americans and 13 Koreans) participated in this experiment. The results showed that, for Korean, the VOT merger of lax and aspirated stops was replicated, and, for English, voiced stops became initially devoiced and voiceless stops became heavily aspirated. English voiceless stops became longer in VOT than Korean counterparts. The results suggest that, similar to Korean stops, English stops may also undergo a sound change. Since it is the first study to be revealed, more convincing evidence is necessary.

O desenvolvimento do padrão de Voice Onset Time das oclusivas surdas iniciais do inglês por aprendizes soteropolitanos: efeitos da instrução explícita

Neste trabalho, investigamos o efeito da instrução explícita de pronúncia no desenvolvimento do padrão de Voice Onset Times (VOT) das oclusivas surdas iniciais do inglês como língua não nativa por aprendizes soteropolitanos. O estudo contou com três coletas de dados, um pré-teste, um pós-teste imediato e um pós-teste postergado, de 16 aprendizes soteropolitanos, divididos em grupos controle e experimental, e com uma sessão de instrução sobre a produção das oclusivas surdas iniciais do inglês. Análises acústicas do VOT são reportadas. Os resultados revelaram que o grupo controle, que não recebeu instrução, não produziu o padrão de VOT esperado para o inglês em nenhuma das coletas. Por outro lado, no grupo experimental, que recebeu instrução explícita, pudemos notar um aumento considerável na duração das oclusivas da L2. Nossos dados revelam efeitos positivos da instrução explícita de pronúncia para o desenvolvimento do VOT da L2 e vão ao encontro de Sancier e Fowler (1997) e Autor 1 (2016), que afirmam que brasileiros são capazes de atingir produções estatisticamente próximas ao esperado para o inglês, ao menos no que concerne ao VOT.

Comparison of VOTs in Mandarin–English bilingual children and corresponding monolingual children and adults

Word-initial stops in Mandarin and English show a distinctive phonological categorization but a similar phonetic realization along the VOT (Voice Onset Time) continuum. Previous research reported that native Mandarin adults produce measurably longer long-lag VOTs than native English adults. The present study examined whether and how the difference between Mandarin and English VOTs is manifested in monolingual children and Mandarin–English bilingual children. The participants included 15 five- to six-year-old sequential bilingual children, 24 corresponding monolingual children (15 Mandarin, 9 English), and 22 monolingual adults (12 Mandarin, 10 English). The bilingual children were divided into two groups (Bi-low and Bi-high) based on the amount of experience in English. Each participant was recorded producing 18 Mandarin words and/or 18 English words containing six stops in each language. The VOT values were measured from the beginning of stop burst to the onset of the voicing. The results showed that the language difference in VOT in the monolingual children was manifested in a pattern similar to the monolingual adults. However, Mandarin and English VOTs showed less separable distributions in the two groups of bilingual children. Further analysis suggested that both groups of bilingual children tended to separate Mandarin and English short-lag VOTs but only the Bi-low children showed different long-lag VOTs between the two languages. These results suggested that due to the bilingual effects and L1–L2 (first language – second language) interactions, even though the bilingual children tried to separate the two VOT systems, they implemented the separation in a different manner than the monolingual speakers.

A Contrastive Study of the Voice Onset Time (VOT) in English and Arabic Languages

تحتوي ألأصوات في اللغة على مختلف الخواص من هذه الخواص هي وقت استهلال الصوت VOT)) وهذه الصفة تشير الى ألأختلاف بين اللفظ للأصوات ألأنفجارية في اللغتين العربية وألأنكليزية ويمكن ان نميز بين ألأصوات ألأنفجارية المهموسة والمهموزة عن طريق (VOT) .
 قسمت الدراسة الى خمسة اجزاء:-
 الجزء ألأول يتضمن المقدمة, المشكلة, الفرضية, الهدف, حدود البحث وقيمة البحث.
 الجزء الثاني يوضح التعاريف وانواع VOT ودورها في اللغة.
 الجزء الثالث يتعامل مع قياس (VOT) وطريقة ادراكه.
 الجزء الرابع يبحث ال (VOT) في اللغتين العربية وألأنكليزية والمقارنة بينهما ونتائج البحث التي توصل لها الباحث.
 ينتهي البحث اخيرا في المصادر التي استخدمت في البحث

Patterns of Short-Term Phonetic Interference in Bilingual Speech

Previous research indicates that alternating between a bilingual’s languages during speech production can lead to short-term increases in cross-language phonetic interaction. However, discrepancies exist between the reported L1–L2 effects in terms of direction and magnitude, and sometimes the effects are not found at all. The present study focused on L1 interference in L2, examining Voice Onset Time (VOT) of English voiceless stops produced by L1-dominant Czech-English bilinguals—interpreter trainees highly proficient in L2-English. We tested two hypotheses: (1) switching between languages induces an immediate increase in L1 interference during code-switching; and (2) due to global language co-activation, an increase in L1-to-L2 interference occurs when bilinguals interpret (translate) a message from L1 into L2 even if they do not produce L1 speech. Fourteen bilinguals uttered L2-English sentences under three conditions: L2-only, code-switching into L2, and interpreting into L2. Against expectation, the results showed that English VOT in the bilingual tasks tended to be longer and less Czech-like compared to the English-only task. This contradicts an earlier finding of L2 VOT converging temporarily towards L1 VOT values for comparable bilingual tasks performed by speakers from the same bilingual population. Participant-level inspection of our data suggests that besides language-background differences, individual language-switching strategies contribute to discrepancies between studies.

F0 as a cue to prosodic structure in voice onset time categorization

This study investigates the effect of F0-based cues to English prosodic structure on the categorization of voice onset time (VOT) continua. Human perceptual systems are capable of extracting relevant phonetic and phonological information in spite of pervasive variation in the speech signal, with prosodic structure being one source of variation. For example, in English VOT in voiceless stops is robustly longer when intonational phrase (IP) initial, versus IP-medial. Kim & Cho (2013) found listeners compensate for perceived IP boundaries, requiring longer VOT to categorize sounds as voiceless when IP-initial. However, because the target sound was in an utterance-medial IP, compensation could have arisen due to the lengthened duration of the preceding IP-final syllable, as in speech rate normalization, instead of due to prosodic structure itself. Mitterer et al. (2016) found categorization shifts solely on the basis of duration, by rendering F0 contours prosodically ambiguous, yet it remains unknown what effect F0 has on categorization when it unambiguously cues prosodic structure. This study tests the hypothesis that compensation is triggered by more than duration normalization, by varying F0 cues independently from duration. Results will be discussed in terms of language-general auditory processing and top-down language-specific influences on segment categorization.

Voice Onset Timing in the English of Spanish Heritage Speakers

The phonological system of bilinguals has been the subject of many recent studies. Several studies have specifically looked at Voice Onset Time (VOT) production in bilinguals in order to answer questions about the phonological system or systems of different types of bilinguals. For example, prior studies have looked at the effects of bilingual phonological production based on age of acquisition of a second language, cross-linguistic influence, and childhood experience with the language. This study will specifically examine the VOT production of a group of bilingual English-Spanish students who are enrolled in a Spanish as a Heritage Language Program (henceforth, SHL) at the University of New Mexico in Albuquerque, New Mexico. This population is of particular interest as Spanish and English have been in long-standing contact in this region of the country. This study will measure the VOT of this diverse group of bilinguals in order to assess whether and to what extent exposure to and/or proficiency in Spanish has an effect on the production of English VOTs in this region of the country.

Effects of following onsets on voice onset time in English

Voice Onset Time (VOT) in English voiceless stops has been shown to be sensitive to place of articulation (Fischer-Jorgensen 1954), to contextual factors such as the height, tenseness, and duration of the following vowel and the voicing of coda consonants (Klatt 1975, Port & Rotunno 1979), to prosodic factors like stress and pitch (Lisker & Abramson 1967), and also to F0 (McCrea & Morris 2005) and speaking rate (Kessinger & Blumstein 1997, Allen 2003). We report two additional factors involving following consonants. We analyzed 120 /p/- and /k/-initial words produced by 148 Canadian English speakers (n = 17742). VOTs of the initial stops were measured semi-automatically and all other segment durations were measured using forced alignment. The results of a mixed-effects regression support earlier findings that VOT is longer in /k/, directly related to following vowel duration, inversely related to speech rate, longer before tense vowels, and shorter before voiceless codas. Additionally, we find that VOT is shorter when the next syllable starts with a phonetically voiceless plosive (i.e., excluding flapped /t/), and that the most relevant measure of vowel duration includes the duration of postvocalic liquids, even those that are typically analyzed as onsets.

Voice onset time in Spanish–English spontaneous code-switching

Research on the phonetics of code-switching has focused on voice onset time (VOT) and has yielded mixed results regarding cross-language interaction, possibly due to differences in data used (scripted vs. spontaneous speech) and populations examined (L1 vs. L2 dominant, early vs. late bilinguals). Here VOT was measured in a corpus of spontaneous code-switching speech elicited from a homogeneous group of early bilinguals in conversation with and without distraction (completion of jigsaw puzzles). The distraction meant to increase cognitive load, a manipulation that could affect phonetic realization. Both English and Spanish VOT were shorter at code-switching points than in comparable monolingual utterances. English VOT lengthened overall under increased cognitive load (but remained shorter in code-switching as compared to the monolingual context). These results support previous findings of VOT shortening in code-switching for both English and Spanish, and confirm that the effect applies in the natural speech of early bilinguals.

Voice onset time of voiceless bilabial and velar stops in 3-year-old bilingual children and their age-matched monolingual peers

This study investigates aspects of voice onset time (VOT) of voiceless bilabial and velar stops in monolingual and bilingual children. VOT poses a special challenge for bilingual Spanish- and English-speaking children because although this VOT distinction exists in both languages, the values differ for the same contrast across Spanish and English. Twenty-four 3-year-olds participated in this study (8 bilingual Spanish–English, 8 monolingual Spanish and 8 monolingual English). The VOT productions of /p/ and /k/ in syllable-initial stressed singleton position were compared across participants. Non-parametric statistical analyses were performed to examine differences (1) between monolinguals and bilinguals and (2) between English and Spanish. The main findings of the study were that monolingual and bilingual children generally differed on VOT in English, but not in Spanish. No statistically significant differences were found between the Spanish and the English VOT of the bilingual children, but the VOT values did differ significantly for monolingual Spanish- versus monolingual English-speaking participants. Our findings were interpreted in terms of Flege’s Speech Learning Model, finding possible evidence for equivalence classification.

French native speakers in the making: From language-general to language-specific voicing boundaries

By examining voice onset time (VOT) discrimination in 4- and 8-month-olds raised in a French-speaking environment, the current study addresses the question of the role played by linguistic experience in the reshaping of the initial perceptual abilities. Results showed that the language-general −30- and +30-ms VOT boundaries are better discriminated than the 0-ms boundary in 4-month-olds, whereas 8-month-olds better discriminate the 0-ms boundary. These data support explanations of speech development stressing the effects of both language-general boundaries and linguistic environment (attunement theory and coupling theory). Results also suggest that the acquisition of the adult voicing boundary (at 0 ms VOT in French vs. +30 ms VOT in English) is faster and more linear in French than in English. This latter aspect of the results might be related to differences in the consistency of VOT distributions of voiced and voiceless stops between languages.

Patterns of acquisition of native voice onset time in English-learning children

Learning to speak involves both mastering the requisite articulatory gestures of one's native language and learning to coordinate those gestures according to the rules of the language. Voice onset time (VOT) acquisition illustrates this point: The child must learn to produce the necessary upper vocal tract and laryngeal gestures and to coordinate them with very precise timing. This longitudinal study examined the acquisition of English VOT by audiotaping seven children at 2 month intervals from first words (around 15 months) to the appearance of three-word sentences (around 30 months) in spontaneous speech. Words with initial stops were excerpted, and (1) the numbers of words produced with intended voiced and voiceless initial stops were counted; (2) VOT was measured; and (3) within-child standard deviations of VOT were measured. Results showed that children (1) initially avoided saying words with voiceless initial stops, (2) initially did not delay the onset of the laryngeal adduction relative to the release of closure as long as adults do for voiceless stops, and (3) were more variable in VOT for voiceless than for voiced stops. Overall these results support a model of acquisition that focuses on the mastery of gestural coordination as opposed to the acquisition of segmental contrasts.

Stability of temporal contrasts across speaking styles in English and Croatian

In this paper, we investigate the effect of clear speech, a distinct, listener-oriented, intelligibility-enhancing mode of speech production, on vowel and stop consonant contrasts along the temporal dimension in English and Croatian. Our previous work has shown that, in addition to enhancing the overall acoustic salience of the speech signal through a decrease in speaking rate and expansion of pitch range, clear speech modifications increased the spectral distances between vowel categories in both languages despite the different sizes of their vowel inventories (+10 in English, five in Croatian). Here, we examine how clear speech affects the duration of English tense (long) vs. lax (short) vowels, English vowels preceding voiced (long) vs. voiceless (short) coda stops, Croatian long vs. short vowels and Croatian and English voice onset time (VOT) duration for voiced and voiceless stops. Overall, the results showed that the proportional distance between the ‘short’ and ‘long’ vowel categories and between the voiced and voiceless stop categories was remarkably stable across the two speaking styles in both languages. These results suggest that, in combination with the spectral enhancement of vowel contrasts, language-specific pronunciation norms along the temporal dimension are maintained in clear and conversational speech.

The production of voice onset time (VOT) by English-speaking children in a Japanese immersion program

This study analyzed the production of voice onset time (VOT) for /p, t, k/ in Japanese and English by English-speaking children (n = 15) in a Japanese immersion program. The immersion children produced Japanese voiceless stops with significantly longer VOT values than the monolingual Japanese children and the immersion teachers, but they produced them with significantly shorter VOT values than their English VOT. This suggests that the immersion students are making a phonetic distinction in VOT between Japanese and English, though their VOT values are still intermediate, compared with the norms of the monolingual speakers and their immersion teachers. In other words, the immersion children implemented the VOT contrast differently from the model they were exposed to, that is, that of the Japanese English bilingual teachers.

Prosodic influences on consonant production in Dutch: Effects of prosodic boundaries, phrasal accent and lexical stress

Prosodic influences on phonetic realizations of four Dutch consonants (/t d s z/) were examined. Sentences were constructed containing these consonants in word-initial position; the factors lexical stress, phrasal accent and prosodic boundary were manipulated between sentences. Eleven Dutch speakers read these sentences aloud. The patterns found in acoustic measurements of these utterances (e.g., voice onset time (VOT), consonant duration, voicing during closure, spectral center of gravity, burst energy) indicate that the low-level phonetic implementation of all four consonants is modulated by prosodic structure. Boundary effects on domain-initial segments were observed in stressed and unstressed syllables, extending previous findings which have been on stressed syllables alone. Three aspects of the data are highlighted. First, shorter VOTs were found for /t/ in prosodically stronger locations (stressed, accented and domain-initial), as opposed to longer VOTs in these positions in English. This suggests that prosodically driven phonetic realization is bounded by language-specific constraints on how phonetic features are specified with phonetic content: Shortened VOT in Dutch reflects enhancement of the phonetic feature {−spread glottis}, while lengthened VOT in English reflects enhancement of {+spread glottis}. Prosodic strengthening therefore appears to operate primarily at the phonetic level, such that prosodically driven enhancement of phonological contrast is determined by phonetic implementation of these (language-specific) phonetic features. Second, an accent effect was observed in stressed and unstressed syllables, and was independent of prosodic boundary size. The domain of accentuation in Dutch is thus larger than the foot. Third, within a prosodic category consisting of those utterances with a boundary tone but no pause, tokens with syntactically defined Phonological Phrase boundaries could be differentiated from the other tokens. This syntactic influence on prosodic phrasing implies the existence of an intermediate-level phrase in the prosodic hierarchy of Dutch.

A Cross-Language Comparison of Speaking Rate Effects on the Production of Voice Onset Time in English and Spanish

Of interest in the current study was how voice inset time (VOT) was influenced by changes in speaking rate across Spanish and English. Three groups of subjects (English monolinguals, Spanish monolinguals and early Spanish-English bilinguals) produced sentences containing voiced and voiceless bilabial stops at different speaking rates. As in previous research, English monolinguals showed rate-dependent effects on their VOT productions: VOT increased as speaking rate decreased. Spanish monolinguals showed a large effect of speaking rate on the duration of prevoicing of the voiced stops. However, they showed only a small effect of rate on the VOT of their voiceless stops. The bilinguals produced VOT values in each language that were nearly identical to their monolingual counterparts. The results from this study indicate that short-lag stops experience minimal variation as a function of speaking rate regardless of the other contrasting phonetic categories within a particular language. In addition, early bilinguals showed evidence of separate representations for voiced and voiceless stops for English and Spanish.