Perception Of Voice Onset Time Research Articles

Development of amplitude modulation, voice onset time, and consonant identification in noise and reverberation.

Children's speech understanding is vulnerable to indoor noise and reverberation: e.g., from classrooms. It is unknown how they develop the ability to use temporal acoustic cues, specifically amplitude modulation (AM) and voice onset time (VOT), which are important for perceiving distorted speech. Through three experiments, we investigated the typical development of AM depth detection in vowels (experiment I), categorical perception of VOT (experiment II), and consonant identification (experiment III) in quiet and in speech-shaped noise (SSN) and mild reverberation in 6- to 14-year-old children. Our findings suggested that AM depth detection using a naturally produced vowel at the rate of the fundamental frequency was particularly difficult for children and with acoustic distortions. While the VOT cue salience was monotonically attenuated with increasing signal-to-noise ratio of SSN, its utility for consonant discrimination was completely removed even under mild reverberation. The reverberant energy decay in distorting critical temporal cues provided further evidence that may explain the error patterns observed in consonant identification. By 11-14 years of age, children approached adult-like performance in consonant discrimination and identification under adverse acoustics, emphasizing the need for good acoustics for younger children as they develop auditory skills to process distorted speech in everyday listening environments.

Exploring the Onset of Phonetic Drift in Voice Onset Time Perception

Recent exposure to a second or foreign language (FL) can influence production and/or perception in the first language (L1), a phenomenon referred to as phonetic drift. The smallest amount of FL exposure shown to effect drift in perception is 1.5 h. The present study examined L1 perception at earlier timepoints of FL exposure, to determine whether the phonetic system is able to resist FL influence at an incipient stage. In a longitudinal pre-test/post-test design, L1 English listeners were exposed to Tagalog under different conditions varying in attention directed to the voice onset time (VOT) plosive contrast in the FL; they then completed an identification task on L1 tokens from VOT continua. In every condition, the likelihood of “voiceless” identifications decreased. This change indicates a shift towards a longer VOT crossover point between “voiced” and “voiceless”, consistent with dissimilatory drift in perception. Listeners in a control condition, however, displayed a similar, albeit less lasting, change in L1 judgments, suggesting that the change arose partly from a task effect. We conclude by discussing directions for future research on phonetic drift in perception.

Perceptual assessment of contrastive voicing in 2-year-old children’s speech by adult and school-age child listeners

Past research assessing perception of voice onset time (VOT) in stops suggests that perceptual acuity improves as a function of age, with adults showing steeper labeling functions and narrower boundary widths. Most work has used synthetic stimuli varying a single acoustic cue, so extending such findings to natural speech may not be straightforward. Perceptual judgments may also be influenced by distributional properties of the dataset, e.g., VOT distributions along a continuum and/or the number of productions in each VOT category. This study will assess how distributional characteristics of naturally produced child speech stimuli, collected from six 2–3-year-old English-speaking children, might influence adult and child labeling behavior. Six exemplars per child were chosen with short-lag /b d/, short-lag /p t/, long-lag /b d/, long-lag /p t/. For each POA and VOT group, /b d/ and /p t/ VOTs were bimodally distributed (shorter for voiced targets), separated by a 5 ms gap. We will seek listening data from 20 adults and 20 children (aged 6–8). We anticipate high and similar accuracy levels for both groups when VOT values are appropriate for the target, but clearer group differences for inappropriate VOTs.

Allophonic perception of VOT contrasts in Spanish children with dyslexia.

IntroductionPrevious studies have evidenced a different mode of speech perception in dyslexia, characterized by the use of allophonic rather than phonemic units. People with dyslexia perceive phonemic features (such as voicing) less accurately than typical readers, but they perceive allophonic features (i.e., language‐independent differences between speech sounds) more accurately.MethodIn this study, we investigated the perception of voicing contrasts in a sample of 204 Spanish children with or without dyslexia. Identification and discrimination data were collected for synthetic sounds varying along three different voice onset time (VOT) continua (ba/pa, de/te, and di/ti). Empirical data will be contrasted with a mathematical model of allophonic perception building up from neural oscillations and auditory temporal processing.ResultsChildren with dyslexia exhibited a general deficit in categorical precision; that is, they discriminated among phonemically contrastive pairs (around 0‐ms VOT) less accurately than did chronological age controls, irrespective of the stimulus continuum. Children with dyslexia also exhibited a higher sensitivity in the discrimination of allophonic features (around ±30‐ms VOT), but only for the stimulus continuum that was based on a nonlexical contrast (ba/pa).ConclusionFitting the neural network model to the data collected for this continuum suggests that allophonic perception is due to a deficit in “subharmonic coupling” between high‐frequency oscillations. Relationships with “temporal sampling framework” theory are discussed.

Cortical Auditory Event-Related Potentials and Categorical Perception of Voice Onset Time in Children With an Auditory Neuropathy Spectrum Disorder.

Objective: This study evaluated cortical encoding of voice onset time (VOT) in quiet and noise, and their potential associations with the behavioral categorical perception of VOT in children with auditory neuropathy spectrum disorder (ANSD).Design: Subjects were 11 children with ANSD ranging in age between 6.4 and 16.2 years. The stimulus was an /aba/-/apa/ vowel-consonant-vowel continuum comprising eight tokens with VOTs ranging from 0 ms (voiced endpoint) to 88 ms (voiceless endpoint). For speech in noise, speech tokens were mixed with the speech-shaped noise from the Hearing In Noise Test at a signal-to-noise ratio (SNR) of +5 dB. Speech-evoked auditory event-related potentials (ERPs) and behavioral categorization perception of VOT were measured in quiet in all subjects, and at an SNR of +5 dB in seven subjects. The stimuli were presented at 35 dB SL (re: pure tone average) or 115 dB SPL if this limit was less than 35 dB SL. In addition to the onset response, the auditory change complex (ACC) elicited by VOT was recorded in eight subjects.Results: Speech evoked ERPs recorded in all subjects consisted of a vertex positive peak (i.e., P1), followed by a trough occurring approximately 100 ms later (i.e., N2). For results measured in quiet, there was no significant difference in categorical boundaries estimated using ERP measures and behavioral procedures. Categorical boundaries estimated in quiet using both ERP and behavioral measures closely correlated with the most-recently measured Phonetically Balanced Kindergarten (PBK) scores. Adding a competing background noise did not affect categorical boundaries estimated using either behavioral or ERP procedures in three subjects. For the other four subjects, categorical boundaries estimated in noise using behavioral measures were prolonged. However, adding background noise only increased categorical boundaries measured using ERPs in three out of these four subjects.Conclusions: VCV continuum can be used to evaluate behavioral identification and the neural encoding of VOT in children with ANSD. In quiet, categorical boundaries of VOT estimated using behavioral measures and ERP recordings are closely associated with speech recognition performance in children with ANSD. Underlying mechanisms for excessive speech perception deficits in noise may vary for individual patients with ANSD.

Manipulation of voice onset time in speech stimuli: A tutorial and flexible Praat script.

Voice onset time (VOT) is an acoustic property of stop consonants that is commonly manipulated in studies of phonetic perception. This paper contains a thorough description of the "progressive cutback and replacement" method of VOT manipulation, and comparison with other VOT manipulation techniques. Other acoustic properties that covary with VOT-such as fundamental frequency and formant transitions-are also discussed, along with considerations for testing VOT perception and its relationship to various other measures of auditory temporal or spectral processing. An implementation of the progressive cutback and replacement method in the Praat scripting language is presented, which is suitable for modifying natural speech for perceptual experiments involving VOT and/or related covarying F0 and intensity cues. Justifications are provided for the stimulus design choices and constraints implemented in the script.

Gender differences in voice onset time perception

It has been known for a while that a gender difference in voice onset time (VOT) production exists such that males typically produce shorter VOTs than females (Swarts, 1992; Robb et al., 2005). However, potential gender differences in VOT perception have not been systematically investigated. This study addresses this question and asks if male and female listeners of English exhibit a different crossover point in a VOT continuum between a voiceless and voiced sound. 11-step VOT continua between /t/ and /d/ (VOT ranges from 70 ms to 5 ms) were created and a set of identification tasks were performed. Results show female listeners switch from a /t/-percept to a /d/-percept at an earlier VOT step (i.e., with a longer VOT) than male listeners do. That is, when female listeners start to categorize a token as a /d/-sound, male listeners still categorize the same token as a /t/-sound. This difference in the perceptual pattern between males and females mirrors their difference in production. VOTs for /t/ are typically shorter for male than female speakers, and male listeners categorize shorter VOT tokens as /t/ more often than female listeners do. This finding highlights the role of social factors like gender in the production-perception link.

Music Training Positively Influences the Preattentive Perception of Voice Onset Time in Children with Dyslexia: A Longitudinal Study.

Previous results showed a positive influence of music training on linguistic abilities at both attentive and preattentive levels. Here, we investigate whether six months of active music training is more efficient than painting training to improve the preattentive processing of phonological parameters based on durations that are often impaired in children with developmental dyslexia (DD). Results were also compared to a control group of Typically Developing (TD) children matched on reading age. We used a Test–Training–Retest procedure and analysed the Mismatch Negativity (MMN) and the N1 and N250 components of the Event-Related Potentials to syllables that differed in Voice Onset Time (VOT), vowel duration, and vowel frequency. Results were clear-cut in showing a normalization of the preattentive processing of VOT in children with DD after music training but not after painting training. They also revealed increased N250 amplitude to duration deviant stimuli in children with DD after music but not painting training, and no training effect on the preattentive processing of frequency. These findings are discussed in view of recent theories of dyslexia pointing to deficits in processing the temporal structure of speech. They clearly encourage the use of active music training for the rehabilitation of children with language impairments.

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

Instructional Effects on Voice Onset Time Perception in L2 Speech Segmentation

This study examined the effects of instruction on the English word boundary perception of Korean learners of English. The focus of this study was the appropriate use of Voice Onset Time (VOT) of English voiceless stops (p, t, k) in word initial (e.g., top) and after word initial s position (e.g., stop) signaling the presence and absence of a word boundary before the stop consonant. There were 48 participants in the study, who were assessed three times: before instruction (pre-test), immediately after instruction (post-test), and five weeks after instruction (delayed post-test). Results revealed that participants’ perceptual accuracy improved significantly in both VOT positions in segmentation after instruction. However, the improvement was more prominent in word initial than after word initial s. Among word initial stop consonants, velar stops were the most difficult to acquire, while after initial s, bilabial stops were the most difficult and alveolar stops were the easiest to acquire.

Dynamic emergence of categorical perception of voice-onset time in human speech cortex

A fundamental challenge in speech perception involves the resolution of a many-to-one mapping from a highly variable, continuous sensory signal onto discrete, perceptually stable categories that bear functional relevance. Recent work has identified signatures of invariance in early neural responses to speech, but the physiological mechanisms that give rise to these categorical representations remain unclear. We employed intracranial recordings in human subjects listening to and categorizing speech stimuli to investigate the spatiotemporal cortical dynamics underlying categorical perception. Stimuli comprised a voice-onset time (VOT) continuum from /b/ (0 ms VOT) to /p/ (50 ms VOT). Results revealed spatially distinct neural populations that respond selectively to tokens from one category (either /b/ or /p/). Within these subpopulations, response amplitude is modulated by stimulus prototypicality for within-category stimuli (e.g., stronger response to 0 ms vs. 10 ms VOT in /b/-selective electrodes). Over the course of a trial, this initially graded encoding of VOT rapidly evolves to reflect properties of the ultimate (categorical) behavioral response function. These same dynamics emerged in a computational neural network model simulating neuronal populations as leaky integrators tuned to detect temporally distributed acoustic cues at precise lags. Our results provide direct evidence that categorical perception of VOT arises dynamically within discrete, phonetically tuned neural populations.

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.

Bilingual exposure influences infant VOT perception

Linking the discrimination of voice onset time (VOT) in infancy with infant language background, we examine the perceptual changes of two VOT contrasts (/b/-/p/ and /ph/-/p/) by Dutch monolingual and bilingual infants from 8 to 15 months of age. Results showed that language exposure and language dominance had a strong impact on monolingual and bilingual infant VOT perceptual patterns. In addition, perceptual turbulence was found at 8–9 months for bilingual infants, and stabilized perception was presented for all infants from 11 months onwards. We thus report a general input-driven developmental VOT perception in both monolingual and bilingual infants, with perceptual turbulence for bilinguals in the second half of the first year of life.

Event-related potentials to an english/spanish syllabic contrast in mexican 10-13-month-old infants.

We report brain electrophysiological responses from 10- to 13-month-old Mexican infants while listening to native and foreign CV-syllable contrasts differing in Voice Onset Time (VOT). All infants showed normal auditory event-related potential (ERP) components. Our analyses showed ERP evidence that Mexican infants are capable of discriminating their native sounds as well as the acoustically salient (aspiration) foreign contrast. The study showed that experience with native language influences VOT perception in Spanish learning infants. The acoustic salience of aspiration is perceived by both Spanish and English learning infants, but exposure provides additional phonetic status to this native-language feature for English learning infants. The effects of early experience and neural commitment as well as the impact of acoustic salience are further discussed.

Perception of Voice Onset Time in Standard Persian initial stops

Perception of Voice Onset Time in Standard Persian initial stops

Categorical Perception of VOT and Lexical Tones in Chinese and the Developmental Course

Speech perception focuses on the mapping between properties of the acoustic signals and linguistic elements such as phonemes.One of the most important features of speech perception is the phenomenon known as categorical perception(CP) that the continuous sensory inputs are coded categorically.CP has an important influence on the developmental time course of speech perception.Although a large amount of research on CP has been conducted in English and other languages,CP(especially its developmental course) in Chinese has been barely studied.Chinese is a tonal language with some specific phonetic characteristics,such as strong aspiration with long positive voice onset time(VOT) and lexical tones characterized by syllable-level f0 contours.However,the questions such as whether the perception of VOT and lexical tones in Chinese is categorical and how they develop with age are still unaddressed.Using the stimuli of VOT and tone continua created by Klatt,the present two studies investigated CP of VOT and lexical tones in Chinese and their developmental course.Using the classical identification and discrimination paradigm,study 1 investigated the perception of Chinese lexical tone continua and VOT continua in adults.The study was comprised of 4 experiments which included identification and discrimination of VOT and tone respectively.Stimuli were presented to 20 adult subjects in each experiment.The results demonstrated that the perceptions of VOT and lexical tones are both categorical for Chinese adults.Study 2 further investigated the developmental course of Chinese phonetic categorization across lexical tone and VOT continua.The experimental design of this study is a 2(entity stimuli:VOT,lexical tone) by 4(age:5ys,6ys,7ys,adults) mixed experiment design.The former was a within-subject factor,while the latter was a between-subject one.Results from Study 2 revealed that six-year-old children already acquired adult-like lexical tone CP competence,but even 7-year-old children were not as good as adults when doing CP of VOT tasks.Therefore,it is proposed that CP of lexical tones is acquired earlier than CP of VOT in Chinese.Further analysis of the correlation between the 2 phonological characteristics showed that they are not correlated with each other.Thus,it is suggested that these two phonetic characteristics are distinct and go through different developmental courses.CP of lexical tone seems to be a phonetic characteristic that is easier to acquire than CP of VOT in Chinese.In conclusion,the findings demonstrated that:(1) the perceptions of both VOT and lexical tones in Chinese are typically categorical for adults;(2) there are different developmental courses for CP of lexical tones and VOT in Chinese.According to the theory proposed by Burnham,we conclude that the Chinese lexical tone is a "robust" contrast and is categorically perceived in early childhood;in contrast,VOT is a "fragile" contrast that requires more time to develop.

Auditory discrimination of voice-onset time and its relationship with reading ability

The perception of voice-onset time (VOT) during dichotic listening provides unique insight regarding auditory discrimination processes and, as such, an opportunity to learn more about individual differences in reading ability. We analysed the responses elicited by four VOT conditions: short–long pairs (SL), where a syllable with a short VOT was presented to the left ear and a syllable with a long VOT was presented to the right ear, as well as long–short (LS), short–short (SS), and long–long (LL) pairs. Stimuli were presented in three attention conditions, where participants were instructed to attend to either the left or right ear, or received no instruction. By around 9.5 years of age children perform similarly to adults in terms of the size and relative magnitude of the right ear advantage (REA) elicited by each of the four VOT conditions. Overall, SL pairs elicited the largest REA and LS pairs elicited a left ear advantage (LEA), reflecting stimulus-driven bottom-up processes. However, children were less able to modulate their responses according to attention condition, reflecting a lack of top-down control. Effective direction of attention to one ear or the other was related to measures of reading accuracy and comprehension, indicating that reading skill is associated with top-down control of bottom-up perceptual processes.

The benefit of variation in cross‐language perception of voice onset time (VOT).

Listeners are consistently able to adjust to perceptually ambiguous sounds (Norris et al., 2003; among others). When listeners are exposed to sounds ambiguous between two phonetic categories, boundaries adjust to the ambiguous signal. Perceptual learning has been suggested to account for adjustment to unfamiliar accents. It is not necessarily true, though, that this flexibility extends to more extreme cases of variation. Many sounds in accented speech are unambiguously mapped to the wrong category (e.g., unaspirated voiceless stops in French‐accented English are perceived as voiced by native English listeners). We examined English listeners’ perception of accented English in a perceptual learning paradigm with two exposure conditions: native French VOT mean and range in words that are lexically unambiguous (e.g., poach, *boach, not pet bet). Perceptual learning completely fails when listeners are exposed to the mean VOT, and in fact, this is coupled with an expanded voiced category, even though the words ...

Language background influences the emergence of voice onset time production and perception.

This study investigates the production and perception of voice onset time (VOT) among preschool children who acquired English and French simultaneously compared to monolingual peers of these two languages. Children participated in this study at the age of 18 months and returned at 24 months for a second session. During each session the children took part in a visual habituation procedure to evaluate discrimination of VOT using edited natural /b/+ vowel and /p/ + vowel syllables in a task format developed by Houston et al. (2007) to assess individual performance. In this task, three VOT values (produced by several talkers) were presented to the children: one within adult norms of the language for voiced bilabial consonants; one within the adult norms of the language for voiceless bilabial consonants; and one between the means for the voiced and voiceless consonants. The children also participated in a structured play session, and their spontaneous productions of word initial stops were acoustically analyzed to measure VOT. Preliminary analysis indicates that accuracy in discriminating VOT precedes production of voicing contrasts for all groups, and monolinguals appear to have developed adultlike perception and production of voicing at a younger age than their bilingual peers.

Natural Boundaries in Gap Detection are Related to Categorical Perception of Stop Consonants

The hypothesis that a natural auditory psychophysical discontinuity contributes to a perceptual category boundary between voiced and voiceless English stop consonants was examined. The relationships between voice onset time (VOT) phonetic boundary and gap-detection thresholds for conditions in which the sounds delimiting the gap were acoustically identical or different were examined in 18 native young adult English speakers. It was specifically hypothesized that between-channel gap-detection thresholds, in contrast to within-channel gap thresholds, would be better predictors of categorical VOT values for listeners. The stimuli used in the between-channel gap-detection task were designed such that dissimilar leading and trailing markers of the gap approximated a stop burst and a following vowel, both in terms of temporal and spectral relationships, while being devoid of phonetic identity. The stimuli used to examine the VOT measure were synthesized bilabial stop syllables in a continuum ranging from /ba/ to /pa/. Statistically significant larger gap thresholds were found for the between-channel conditions than for the within-channel condition (p < 0.05). The center frequency of the trailing marker affected the between-channel gap thresholds with the thresholds improving as the center frequency increased (p < 0.05). Statistically significant positive correlations and predictive linear relations were found between VOT phonetic boundaries and between-channel gap thresholds (p < 0.05) but not within-channel gap thresholds (p > 0.05). A relationship between the phonetic boundary of voiced-voiceless speech sounds and the auditory temporal resolution task of detecting gaps placed within dissimilar markers, regardless of the center frequency of the trailing marker noise burst, was demonstrated. Detection of gaps between different nonspeech acoustic markers and categorical perception of VOT seems to share the same underlying perceptual timing mechanisms in native English speakers.