Voice Onset Time Range Research Articles

Non-nutritive suck and voice onset time: Examining infant oromotor coordination.

The variability of a child's voice onset time (VOT) decreases during development as they learn to coordinate upper vocal tract and laryngeal articulatory gestures. Yet, little is known about the relationship between VOT and other early motor tasks. The aims of this study were to evaluate the relationship between infant vocalization and another early oromotor task, non-nutritive suck (NNS). Twenty-five full-term infants (11 male, 14 female) completed this study. NNS was measured with a customized pacifier at 3 months to evaluate this early reflex. Measures of mean VOT and variability of VOT (measured via coefficient of variation) were collected from 12-month-old infants using a Language Environmental Analysis device. Variability of VOTs at 12 months was significantly related to NNS measures at 3-months. Increased VOT variability was primarily driven by increased NNS intraburst frequency and increased NNS burst duration. There were no relationships between average VOT or range of VOT and NNS measures. Findings from this pilot study indicate a relationship between NNS measures of intraburst frequency and burst duration and VOT variability. Infants with increased NNS intraburst frequency and NNS burst duration had increased VOT variability, suggesting a relationship between the development of VOT and NNS in the first year of life. Future work is needed to continue to examine the relationship between these early oromotor actions and to evaluate how this may impact later speech development.

An analysis of the perception of stop consonants in bilinguals and monolinguals in different phonetic contexts: A range-based language cueing approach.

Bilinguals' observed perceptual shift across language contexts for shared acoustic properties between their languages supports the idea that bilinguals, but not monolinguals, develop two phonemic representations for the same acoustic property. This phenomenon is known as the double phonemic boundary. This investigation replicated previous findings of bilinguals' double phonemic boundary across a series of go/no-go tasks while controlling for known confounding effects in speech perception (i.e., contrast effects) and differences in resource allocation between bilinguals and monolinguals (i.e., left-hand or right-hand response). Using a range-base language cueing approach, we designed 2 experiments. The first experiment tested whether a voice onset time (VOT) range representative of either Spanish or English phonetic categories can cue bilinguals, but not monolinguals, to use language-specific perceptual routines. The second experiment tested a VOT range with a mixture of Spanish and English phonetic categories to determine whether directing attention to a specific phonetic category can disambiguate the competition of the nonattended category. The results for Experiment 1 showed that bilinguals can rely on the distributional patterns of their native phonetic categories to activate specific language modes. Experiment 2 showed that attention can change the weight given to a native phonetic distinction. However, this process is restricted by the internal phonetic composition of the native language(s).

Phonetic categorization and discrimination of voice onset time under divided attention.

Event durations are perceived to be shorter under divided attention. "Time shrinkage" is thought to be due to rapid attentional switches between tasks, leading to a loss of input samples, and hence, an under-estimation of duration. However, few studies have considered whether this phenomenon applies to durations relevant to time-based phonetic categorization. In this study, participants categorized auditory stimuli varying in voice onset time (VOT) as /ɡ/ or /k/. They did so under focused attention (auditory task alone) or while performing a low-level visual task at the same time (divided attention). Under divided attention, there was increased response imprecision but no bias toward hearing /ɡ/, the shorter-VOT sound. It is concluded that sample loss under divided attention does not apply to the perception of phonetic contrasts within the VOT range.

Challenges in multi-language pronunciation teaching: A cross-linguistic study of Chinese students’ perception of voiced and voiceless stops

This article reports on a cross-linguistic study of 58 Chinese students’ perception of voiced and voiceless stops in their third language (L3). The participants were Japanese, Russian, or Spanish major students in a Chinese university, who were beginner learners of these languages but who had all learned English as their second language (L2) for over 10 years. The purpose of this study was to investigate the L3 learners’ perceptual differences in the stop categories, and analyze the effects of the learners’ multi-language background on their perception of L3 stops. Results from the perception experiment showed that: 1) the value and range of voice onset time (VOT) play an essential role in Chinese students’ perception of voiceless stops; and 2) the pre-voicing during closure is the key to Chinese students’ perception of voiced stops. We attribute their difficulty in perceiving L3 voiceless stops to the similarity in the phonemic range of voiceless stops between the learners’ L3 and their L1 and L2, as this leads to confusion in perception. On the other hand, the dissimilarity between L3 voiced stops and those of L1 and L2 is conducive to the students’ perception of L3 voiced stops. Findings from this study provide empirical evidence for the effect of similarity and dissimilarity in speech sounds as proposed in earlier phonology acquisition theories, and they can also inform the pedagogy of multi-language education.

Auditory enhancement and second language experience in Spanish and English weighting of secondary voicing cues

The role of secondary cues in voicing categorization was investigated in three listener groups: Monolingual English (n = 20) and Spanish speakers (n = 20), and Spanish speakers with significant English experience (n = 16). Results showed that, in all three groups, participants used onset f0 in making voicing decisions only in the positive voice onset time (VOT) range (short lag and long lag tokens), while there was no effect of onset f0 on voicing categorization within the negative VOT range (voicing lead tokens) for any of the participant groups. These results support an auditory enhancement view of perceptual cue weighting: Onset f0 serves as a secondary cue to voicing only in the positive VOT range where it is not overshadowed by the presence of pre-voicing. Moreover, results showed that Spanish learners of English gave a significantly greater weight to onset f0 in their voicing decisions than did listeners in either of the other two groups. This result supports the view that learners may overweight secondary cues to distinguish between non-native categories that are assimilated to the same native category on the basis of a primary cue.

Development of assisting system for learning Chinese aspirated sounds

Chinese aspirates are generally difficult for Japanese to pronounce and perceive. In order to assist Japanese students to learn Chinese, the authors attempt to build a system to automatically evaluate the pronunciation of Chinese aspirates by Japanese students. To do so, this study analyzed 21 single‐vowel syllables of six different Chinese aspirates, bilabial, alveolar, velar, palatal, retroflex, and dental using two evaluation parameters: the voice onset time (VOT) and mean breathing power during VOT. The speech materials were uttered by nine Japanese students and nine native Chinese speakers. It is found that for a give aspirate, the longer the VOT is, the better the score is, as is generally said. But we found that an aspirate with a larger breathing power acquires good mark even with a shorter VOT in a certain range of VOT. The testing results showed that a combination of these two parameters can distinguish aspirated and unaspirated sounds quite well. To achieve an assisting system, we developed a m...

Enhancement between voice onset time (VOT) and F0: Evidence from Kera voicing perception

Previous research on production data from Kera (a Chadic tone language) has shown that tone plays a major contrastive role, whereas VOT has a lesser role which could indicate an ‘‘enhancing’’ relationship. This paper investigates the roles of VOT and F0 in Kera voicing perception, and compares this to the nontonal language English. Fifteen Kera and 15 English subjects were given voicing judgment tasks over 200 tokens that had been manipulated in PRAAT to cover a range of VOT and F0 values. The results show a marked difference in English and Kera perception reflecting the phonological differences between the two languages. For Kera, F0 is of major importance, while the VOT plays a lesser role in the judgment. The present findings are consistent with a view that whereas in English, the VOT is contrastive and F0 arguably acts as an enhancing cue, in Kera, the tone is the main contrastive cue to voicing perception while the VOT values enhance the tone cues. A bonus finding from the perception tests is that the relationship between VOT and F0 in Kera voicing perception tasks depends on their exposure to French during childhood.

Native-language influence on phonetic perception in Dutch–English bilinguals

We examined how native-language experience influences processing a second language, focusing on how native Dutch listeners who learned English as a second language perceive the English voiceless consonant /p/. Previous research [J. E. Flege and W. Eefting, Speech Commun. 6, 185–202 (1987)] shows that the voiced–voiceless boundary for an (English-based) voice-onset-time (VOT) series is located at a shorter VOT for such bilingual listeners than for native English listeners, consistent with the fact that voiceless stops are produced with shorter VOTs in Dutch than in English. We asked whether such bilinguals also differ from native English listeners in which stimuli throughout the series are perceived as reasonable exemplars of /p/. Native English listeners and native Dutch listeners were tested on a three-choice identification task with an (English-based) extended VOT series that ranged from /ba/ to /pa/ to an ‘‘unnatural’’ exaggerated /pa/, labeled */pa/. Both the /b/-/p/ and /p/-*/p/ boundaries were located at shorter VOTs for the native Dutch than the native English listeners, indicating that Dutch native-language experience influenced the entire range of VOTs perceived as reasonable exemplars of the /p/ category. Thus native-language experience has a comprehensive influence on the mapping from acoustic signal to phonetic category. [Work supported by NIH/NIDCD.]

Effects of interaural time differences on the responses of chinchilla inferior colliculus neurons to consonant-vowel syllables

The responses of 100 inferior colliculus neurons to syllables differing in voice onset time (VOT) presented binaurally were studied. As in a previous study of monaural responses (Chen et al., 1996), the responses consisted of 1–3 response ‘components’, referred to as release responses, VOT responses or vowel responses. The discharge rate of all response components could vary cyclically with the interaural time difference (ITD). The maximal rate often occurred at an ITD around +0.2 ms (contralateral ear leading). Response frequencies (RF) based on the periodicity of the delay curves varied with the characteristic frequency (CF) and VOT. RF also varied across response components. Overall, RF was correlated with the ‘most effective frequency’, the spectral component with the highest amplitude, relative to the tuning curve. VOT response latency for a given syllable could change by a few ms with ITD, but those changes were small, relative to the range of latencies observed over the entire range of VOTs. Changes in ITD produced large changes in the overall shape of the peristimulus time histogram. There was no relation between the histogram shape and perceptual consonant categories.

Voicing judgements by chinchillas trained with a reward paradigm

Experiments were performed to replicate and extend previous findings of similar categorization of voiced/voiceless consonant–vowel (CV) syllables by humans and chinchillas. A reward paradigm was applied to the question of how stimulus range affects the voice-onset-time (VOT) corresponding to the voiced/voiceless category boundary. Each of four adult chinchillas and four human subjects identified synthetic CV syllables as voiced (/ba/, /da/, /ga/) or voiceless (/pa/, /ta/, /ka/) using voiceless standards of either 80 or 120 ms. In both humans and animals, extending the VOT range from 80 to 120 ms shifted category boundaries to longer VOTs, but to a different extent across listeners. Control experiments suggested that listeners were attending to different phonetic cues in a manner that depended on the listener, rather than on species. The results are interpreted in terms of similar contextual effects and use of multiple phonetic cues to voicing in humans and animals.

A cross-language study of range of voice onset time in the perception of initial stop voicing

A series of experiments was carried out to compare the extent of range effects in the phonetic categorization of voice onset time (VOT) by speakers of Polish and of English, two languages which contrast different VOT categories. Results indicate that Poles are more prone to range effects than are Americans. For acoustic continua with appreciable numbers of prevoiced stimuli, monolingual Polish speakers’ perceptual boundaries fall in the gap between their production categories. For ranges of VOT which include few prevoiced stimuli, their boundaries are substantially shifted. Americans show no shifts of this type, although they do show some small shifts. It was determined that the much smaller shifts shown by the American subjects were not due to expectations about the test. Results are interpreted in terms of the different VOT contrasts involved: their spacing along the VOT continuum, and their psychophysical basis.

Differences in production and perception of VOT in Polish and English

English and Polish use different Voice Onset Time (VOT) categories to contrast voiced and voicelesstops: short lag and long lag (English) versus prevoiced and short lag (Polish). When VOT is measured for word‐initial stops in minimal pairs, sentences, and conversation, the VOT distributions for voiced and voiceless stops are clearly separated in Polish, but not always in English, especially in casual speech [Lisker and Abramson, Language and Speech 10, 1–28 (1967); Moslin, Brown University dissertation (1978)]. The perception of VOT in synthetic stimuli was compared with production data for Polish and American English listeners. Both groups labeled stimuli in three continua that varied in range of VOT: −20 to + 80, −100 to +50, and −100 to +20 ms VOT. The Polish, but not the American, listeners showed a mean boundary shift (from +20 to +4 ms VOT) as a function of these ranges. Thus the Polish VOT perceptual categories are somewhat unstable and do not always match the VOT production categories, although th...