Short-lag Voice Onset Time Research Articles

Stop voicing perception in the societal and heritage language of Spanish-English bilingual preschoolers: The role of age, input quantity and input diversity

This is the first study to examine stop voicing perception in the societal (English) and heritage language (Spanish) of bilingual preschoolers. The study a) compares bilinguals’ English perception patterns to those of monolinguals; b) it examines how child-internal (age) and external variables (input quantity and input diversity) predict English and Spanish perceptual performance; and c) it compares bilinguals’ perception patterns across languages. Perception was assessed through a forced-choice minimal-pair identification task in which children heard synthesized audio stimuli that varied systematically along a /p-b/ and /t-d/ Voice Onset Time (VOT) continuum and were asked to match them with one of two pictures for each contrast. The results of Bayesian mixed-effects logistic regression analyses indicate that the bilinguals’ category boundary for English stops was impacted by their experience with Spanish, with more short-lag VOT tokens being perceived as voiceless consistent with Spanish VOT. Age solely predicted English perceptual skills, whereas input quantity was the only moderator of Spanish perceptual performance. Finally, the bilingual children showed separate stop voicing contrasts in each language, although perceptual performance was already more mature in English by preschool age. Implications for theories of bilingual speech learning and the role of sociolinguistic variables are discussed.

Speaking Rate, Oro-Laryngeal Timing, and Place of Articulation Effects on Burst Amplitude: Evidence From English and Tamil.

The relationship between speaking rate and burst amplitude was investigated in plosives with differing oro-laryngeal timing: long-lag voice-onset time (VOT) (North American English) and short-lag VOT (Indian Tamil). Burst amplitude (reflecting both intraoral pressure and flow geometry of the oral channel) was hypothesized to decrease in pre-vocalic plosive syllables with the increase in speaking rate, which imposes temporal constraints on both intraoral pressure buildup behind the oral occlusion and respiratory air flow. The results showed that decreased vowel duration (which is associated with increased speaking rate) led to decreased burst amplitude in both short- and long-lag plosives. Aggregate models of bilabial and velar plosives (found in both languages) suggested lower burst amplitudes in short-lag stops. Place-of-articulation effects in both languages were consistent with models of stop consonant acoustics, and place interactions with vowel duration were most apparent with long-lag English stops. The results are discussed in terms of speaking rate and language-internal forces, contributing to burst amplitude variation and their implications for speech perception and potential to affect lenition phenomena.

Voice onset time (VOT) of L3 Spanish /ptk/ by multilingual heritage speakers of Ukrainian and Polish

This study provides an acoustic analysis of voice onset time (VOT) of voiceless stops /ptk/ in Spanish, produced by heritage speakers (HSs) of Ukrainian and of Polish who are English-dominant and beginner or intermediate learners of Spanish as a third language (L3). Given that both Ukrainian and Polish, like Spanish and unlike English, are characterized by short-lag VOT, data were collected from six Ukrainian HSs and 11 Polish HSs in their heritage language (HL), in English, and in Spanish to compare potential effects of the HL on L3 VOT production. VOT was analyzed in three task types. The goals were: 1) to determine whether VOT values produced in Spanish by Ukrainian and Polish HSs are more reflective of VOTs in the HL or in English, and 2) to determine the effect of task type on VOT. Data show that Ukrainian and Polish HSs’ VOTs in Spanish are shorter than those of L2 Spanish learners whose L1 is English, indicating a HL rather than dominant language influence on L3 VOT. Results suggest that the most crucial factors in L3 phonological acquisition are: 1) structural similarity between HL and L3, and 2) L3 proficiency (not language dominance). VOT was also affected by task type: like L1 Spanish speakers, VOT of Ukrainian HSs increases as task formality increases. This paper fills research gaps in HL and L3 phonetics/phonology as to the effects of a HL on the acquisition of subsequent sound systems in adulthood.

Effect of emphasis spread on VOT in coronal stops in Qatari Arabic

Emphasis (contrastive pharyngealization of coronals) in Arabic spreads from an emphatic consonant to neighboring segments. Previous research suggests that in addition to changing spectral characteristics of adjacent segments, emphasis might affect voice onset time (VOT) of voiceless stops because emphatic stops in Arabic dialects have considerably shorter VOT than their plain cognates. No study investigated whether emphatic co-articulation could shorten VOT in plain stops produced in emphatic environment. The present study investigates changes in VOT in syllable-initial /t/ using production data from sixteen speakers of Qatari Arabic, who read non-word syllables with initial plain and emphatic stops /t/ and /ṭ/ adjacent to another plain or emphatic consonant. The results show that emphasis spread is a gradient process that affects only spectral characteristics of segments, causing changes in vowel formants and spectral centre of gravity of stops. Long-lag VOT in plain /t/, however, was not shortened in emphatic syllables. The findings suggest that shorter VOT in voiceless emphatic stops in Qatari Arabic is not a mechanical aftermath of pharyngealization but, rather, a phonological requirement to maintain contrast between long-lag and short-lag VOT in plain and emphatic stops.

Spit or sbit? ST-type consonant clusters in the speech of Polish learners of English

This paper presents two small-scale acoustic phonetic studies investigating the pronunciation of sibilant-stop (ST) consonant clusters in Polish, and in the L2 speech of L1 Polish learners of English. In English, aspiration of fortis stops is not attested in the post-/s/ context. Rather, short-lag voice onset time (VOT) measures are observed in L1 English in post-/s/ stop consonants, a phonetic weakening that renders them phonetically similar in terms of VOT to lenis stops in initial position. In Polish, both voiced and voiceless stops may appear after sibilant fricatives. The acoustic results suggest that (1) L1 Polish does not weaken its stops in ST clusters, and (2) that more L1 Polish speakers exhibit some weakening in their L2 English clusters as a function of proficiency, but do not produce native-like VOTs in ST sequences. Implications of these findings for L2 speech research and the phonological status of ST clusters are discussed.

Effect of emphasis spread on coronal stop articulation in Qatari Arabic

Emphasis (contrastive uvularisation) in Arabic spreads from an emphatic consonant to neighboring segments (Davis 1995). The effect of emphasis spread on a consonant is manifested as lowering of its spectral mean (Jongman et al. 2011). Although stop consonants reveal a strong effect of emphasis, it is not known how emphasis spread affects other acoustic properties of stops, e.g. voice onset time (VOT). Previous studies (Kulikov 2018) showed that VOT and emphasis are linked in speech production: plain /t/ in Gulf Arabic is aspirated; emphatic /ṭ/ has short-lag VOT. Phonological theory predicts that plain /t/ should become more emphatic in emphatic context, which might reduce stop VOT as well. The current study investigates the effect of emphasis spread on VOT in word-initial coronal stops in Qatari Arabic. The stimuli, produced by sixteen native speakers of Qatari Arabic, contained target plain and emphatic stops /t/, /ṭ/ followed by short or long low vowel, and plain coronal obstruents /t, s, ð/ or their emphatic counterparts /ṭ, ṣ, ð̣/. The acoustic analysis included measurements of VOT and spectral mean of burst in the stop, and F1, F2, F3 frequencies at the vowel beginning, middle and end. The results showed that final emphatic obstruent triggered emphasis spread across the syllable. The effect of emphasis on the vowel was stronger next to the emphatic obstruent (p < .01). Spectral mean of burst in plain /t/ was lower in the emphatic context (D = 276 Hz, p = .05). VOT, however, was not affected by emphasis spread. Plain /t/ had long-lag VOT averaging 52 ms; emphatic /ṭ/ had short-lag VOT averaging 17 ms. These values were not different in emphatic context (p = .743). The findings demonstrate that emphasis spread within a syllable affects only spectral characteristics of a coronal stop. Emphaticness of plain /t/ did not affect its VOT and did not result in complete transformation of the stop category

Dominance, mode, and individual variation in bilingual speech production and perception

AbstractEarly Spanish-English bilinguals and English controls were tested on the production and perception of negative, short-lag, and long-lag Voice Onset Time (VOT), VOT types spanning the Spanish and English phonetic categories: phonologically, negative and short-lag VOT stops are distinct phonemes in Spanish, but realizations of voiced stops in English. Dominance was critical: more English-dominant bilinguals produced more short-lag VOT stops in response to negative VOT stimuli, and were also less accurate than more balanced bilinguals at discriminating negative from short-lag VOT. Bilinguals performed similarly to monolinguals overall, but they produced more negative VOT tokens and shorter short-lag VOT in response to negative VOT. Their productions were also less well correlated with perception and showed more variation between individuals. These results highlight the variable nature of bilingual production and perception, and demonstrate the need to consider language dominance, individual variation, as well as modalities and tasks when studying bilinguals.

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.

Moro voicelessness dissimilation and binary[voice]

This paper reports on a pattern of voicelessness dissimilation in the Kordofanian language Moro. Voiceless stops and affricates become voiced before a voiceless obstruent in a transvocalic configuration. The dissimilation is robust, and productive across morphological contexts. Phonetically, voicing in Moro is realised as a difference between prevoicing and short-lag voice onset time. This makes [voice] the most realistic featural characterisation; using another feature like [spread glottis] in lieu of [–voice] doesn't explain the contrast. Consequently, dissimilation of voicelessness in Moro is strong evidence that [voice] is a binary feature, and that […voice] may be phonologically active despite being ‘unmarked’. We show that when [–voice] is admitted, the Moro pattern is straightforwardly analysed on a par with other cases of dissimilation. Our analysis uses the theory of surface correspondence, which carries no crucial assumptions about markedness; other theories of dissimilation are considered in an online supplement.

Perception of voice onset time in Singapore English

This study investigates how voice onset time (VOT) is perceived in Singapore English (SgE). SgE research acknowledges that Singaporeans linguistically accommodate their listeners—varying between using Standard Singapore English (SSE) or Singlish (colloquial SgE) depending on addressee. Liu 2011 (n.p.) suggests these linguistic accommodations are reflected in VOT production, finding Singaporeans to produce more short-lag VOT (indicative of Singlish) when speaking to other Singaporeans and longer VOT (indicative of SSE) when speaking to Americans. Though these are sub-categorical shifts, they demonstrate the utility of VOT in speakers’ efforts when accommodating listeners. The current study tests whether VOT is also available as a salient and social perceptual cue. Three listening experiments investigate (1) Singaporeans’ baseline categorical perception of a /ba/-/pa/ continuum, (2) whether this baseline is affected when heard with socially salient pictures (i.e., linguistic stereotypes—an ah lian or a business woman), and (3) whether dialectal carrier phrases—whether stimuli are presented within a SSE or Singlish phrase—affects perception of the same stimuli. Preliminary results show listener age and educational background, which allude to an effect of dialectal experience (Sumner and Samuel 2009), play important roles in the perception of VOT.

Perception Abilities of L1 Cypriot Greek Listeners - Types of Errors Involving Plosive Consonants in L2 English.

This paper investigates the difficulties adult second language (L2) users of English encounter with plosive consonants in the L2. It presents the results of a task examining the acquisition of plosive voicing contrasts by college students with Cypriot Greek (CG) linguistic background. The task focused on the types of errors involving plosive consonants indicating that performance was significantly better in the voiceless plosive category. Participants were able to perceive voiced plosives but they treated such instances as a /nasal+voiced plosive/ sequence. Therefore, the question raised concerns different phonological contrasts realised through similar phonetic cues. The patterns observed suggested that this gap between phonetic cues and phonological contrast might explain why CG users have difficulties perceiving voiced English plosives. In this context, voice onset time (VOT) differences between the L1 and L2 are of crucial importance. In English, voiced plosives are characterised by short lag VOT while their voiceless counterparts fall within the long lag VOT continuum. The same phonetic contrast is used in CG to differentiate between single and geminate voiceless plosives. The results are discussed in relation to the frameworks of second language phonology and speech perception suggesting that the difficulties faced by the L2 listeners support the operation of a phonetic-phonological challenge.

Phonological status, not voice onset time, determines the acoustic realization of onset f0 as a secondary voicing cue in Spanish and English

The covariation of onset f0 with voice onset time (VOT) was examined across and within phonological voicing categories in two languages, English and Spanish. The results showed a significant co-dependency between onset f0 and VOT across phonological voicing categories but not within categories, in both languages. Thus, English short lag and long lag VOT stops, which contrast phonologically, were found to differ significantly in onset f0. Similarly, Spanish short lag and lead VOT tokens are phonologically contrastive and also differed significantly in terms of onset f0. In contrast, English short lag and lead VOT stops, which are sub-phonemic variants of the same phonological category, did not differ in terms of onset f0. These results highlight the importance of phonological factor in determining the pattern of covariation between VOT and onset f0.

Quantity and laryngeal contrasts in Norwegian

This paper reports on the results of an investigation of the fortis–lenis contrast in stops and the complementary quantity contrast in Norwegian and compares these same contrasts in two dialects of Swedish. The data show that in initial position one series of stops has consistently long-lag Voice Onset Time (VOT) and this series is also voiceless in post-vocalic position, often with some preaspiration. The other series can be produced with either prevoicing or short-lag VOT in initial position and is almost always fully voiced in post-vocalic position. These results support the claim that both phonological features [voice] and [spread glottis] are active in Norwegian. The quantity contrast (VC: vs. V:C) was robust for all speakers, but the durational difference between the two quantity patterns was greater for females than for males. Overall the durational difference between the two quantity types in Norwegian was found to be similar to that in Central Standard Swedish, but not as great as in Fenno-Swedish.

Voice onset time is necessary but not always sufficient to describe acquisition of voiced stops: The cases of Greek and Japanese

The age at which children master adult-like voiced stops can generally be predicted by voice onset time (VOT): stops with optional short lag are early, those with obligatory lead are late. However, Japanese voiced stops are late despite having a short lag variant, whereas Greek voiced stops are early despite having consistent voicing lead. This cross-sectional study examines the acoustics of word-initial stops produced by English-, Japanese-, and Greek-speaking children aged 2–5, to investigate how these seemingly exceptional mastery patterns relate to use of other phonetic correlates. Productions were analyzed for VOT, f0 and spectral tilt (H1−H2) in Japanese and English, and for amplitude trajectory in Greek and Japanese. Japanese voiceless stops have intermediate lag VOT values, so other “secondary” cues are needed to differentiate them from the voiced short lag VOT variant. Greek voiced stops are optionally prenasalized, and the amplitude trajectory for the voice bar during closure suggests that younger children use a greater degree of nasal venting to create the aerodynamic conditions necessary for voicing lead. Taken together, the findings suggest that VOT must be supplemented by measurements of other language-specific acoustic properties to explain the mastery pattern of voiced stops in some languages.

Why are Korean tense stops acquired so early?: The role of acoustic properties

Transcription-based studies have shown that tense stops appear before aspirated or lax stops in most Korean-acquiring children's speech. This order of mastery is predicted by the short-lag voice onset time (VOT) values of Korean tense stops, as this is the earliest acquired phonation type across languages. However, the tense stop also has greater motor demands than the other two phonation types, given its pressed voice quality (negative H1–H2) and its relatively high f0 value at vowel onset, word-initially. In order to explain the observed order of mastery of Korean stops, we need a more sensitive quantitative model of the role of multiple acoustic parameters in production and perception. This study explores the relationship between native speakers' transcriptions/categorizations of children's stop productions and three acoustic characteristics (VOT, H1–H2 and f0). The results showed that the primary acoustic parameter that adult listeners used to differentiate tense vs. non-tense stops was VOT. Listeners used VOT and the additional acoustic parameter of f0 to differentiate lax vs. aspirated stops. Thus, the early acquisition of tense stops is explained both by their short-lag VOT values and the fact that children need to learn to control only a single acoustic parameter to produce them.

Control of short lag VOT (voice-onset time) for voiced English stops

The American English stops /b/, /d/, and /g/ are produced with negative VOT (−150–0 ms) or short-lag VOT (0–30 ms). These two variants have been shown to occur with approximately equal frequency across speakers, although individual preferences are common. It has been hypothesized that the characteristic VOTs of short-lag stops are determined by relatively simpler articulatory control mechanisms than negative VOT variants. Specifically, if the vocal folds are approximated prior to constriction release, and intraoral pressure is vented only at the point of maximum constriction (without supraglottal expansion), the VOT will be determined by the venting process controlled by the time-varying constriction aperture. Thus, the release kinematics could account for effects of place of articulation and vowel context on short-lag VOTs. In the current work, the plausibility of this hypothesis is evaluated. The kinematics of constriction release gestures was examined from x-ray microbeam data. Descriptions of the time-varying geometries of constriction releases were input to a simple model of breath-stream dynamics and simulated VOT values were obtained. The descriptive and simulated data are consistent with the hypothesis that the characteristic durations of short-lag VOTs are determined by the venting process controlled by the supraglottal stop release gesture.

Hemispheric lateralization of the neural encoding of temporal speech features: a whole-head magnetencephalography study

Using a passive oddball design (randomized series of standard [frequent] and deviant [rare] stimuli), the present study investigated the neural encoding of syllables differing in a duration parameter (/da/=short-lag voice onset time [VOT], /ta/=long-lag VOT) by means of whole-head magnetencephalography (MEG). Dipolar activities at the level of the supratemporal planes allowed to explain the evoked magnetic fields. The N1m/P2m-complex (magnetic equivalent to the N1/P2-wave of the electroencephalogram) in response to standard stimuli showed bilateral symmetric distribution. Furthermore, the latency of P2m significantly depended on VOT. Finally, the mismatch response to the deviant /da/-syllables—which represent in German a very frequent word (English: `here' or `there')— evolved significantly earlier in the left hemisphere as compared to the right side. In conclusion, processing speed may be an important aspect of the hemispheric specialization of language.

Effects of speaking rate on voice-onset time in Thai, French, and English

This study investigated the effect of speaking rate on stop consonant production in three languages which have different phonetic categories of voicing. Voice-onset time (VOT) distributions and mean VOT values were examined for initial labial and alveolar stop consonants produced in CV(C) words in isolation and in context at both slow and fast rates of speech. Results revealed that the short lag category did not change as a function of speaking rate in any of the three languages examined, although VOT values for long lag (Thai and English) and pre-voiced (Thai and French) stop consonants were affected by changes in speaking rate. However, the shift of the long lag and pre-voiced categories toward the short lag VOT values in the fast rate condition resulted in little overlap between voicing categories. Implications of these results for the nature of phonetic categories are discussed.

Perceptual switching in Spanish/English bilinguals

Previous studies have shown that bilingual native speakers of languages in which /p t k/ are realized with short-lag voice onset time (VOT) values identify stops with short-lag VOT as voiceless more often in an L1 perceptual “set” than in an L2 (English) set. The purpose of this study was to explore the basis of language set effects. The listeners in Experiment 1 identified nine short-lag Spanish /t/ tokens as “t” or “d”. The Spanish /t/s were identified as “t” more often when they were presented along with short-lag English /d/ tokens than when they were presented along with long-lag English /t/ tokens. Much the same small “phonetic context” effect was observed for Spanish and English monolinguals and for two groups of Spanish/English bilinguals. As expected, native Spanish listeners identified the Spanish /t/s as “t” more often than the native English listeners. The fact that native English listeners often identified the Spanish /t/s as “t” indicated that VOT was not an overriding cue to the voicing feature for them. In Experiment 2, the short-lag Spanish /t/ tokens were presented in Spanish and English perceptual sets. Much the same small “language set” effect was observed for the monolingual and bilingual listeners. The size of the “phonetic context” effect in Experiment 1 and the “language set” effect of Experiment 2 was much the same for most tokens. Detailed acoustic analyses failed to reveal acoustic dimensions that would reliably differentiate the short-lag Spanish /t/ tokens that were predominantly identified as “t” from those that were ambiguous between “ t” and “d”. Taken together, the results indicate that the so-called language set effects observed for bilinguals in previous studies probably do not arise from the application of different language-specific criteria for voicelessness to naturally produced stops with short-lag VOT.

Imitation of a VOT continuum by native speakers of English and Spanish: evidence for phonetic category formation.

This study examined imitation of a voice onset time (VOT) continuum ranging from/da/to/ta/by by subjects differing in age and/or linguistic experience. The subjects did not reproduce the incremental increases in VOT linearly, but instead showed abrupt shifts in VOT between two or three VOT response "modes." The location of the response shifts occurred at the same location as phoneme boundaries obtained in a previous identification experiment. This supports the view that the stimuli were categorized before being imitated. Children and adults who spoke just Spanish generally produced only lead and short-lag VOT responses. English monolinguals tended to produce stops with only short-lag and long-lag VOT values. The native Spanish adults and children who spoke English, on the other hand, produced stops with VOT values falling into all three model VOT ranges. This was interpreted to mean that they had established a phonetic category [th] with which to implement the voiceless aspirated realizations of /t/ in English. Their inability to produce English /p,t,k/ with the same values as native speakers of English must therefore be attributed to the information specified in their new English phonetic categories (which might be incorrect as the result of exposure to Spanish-accented English), to partially formed phonetic realization rules, or both.