Stop Voicing Research Articles

Variation in VOT in English child-directed speech of English-Mandarin and English-Malay early bilinguals in Singapore

ABSTRACT Variability has been observed in the phonetic/phonological properties of child-directed speech from late-second language bilingual caregivers, but less is known about input variation among early bilinguals in multi-dialectal/multilingual contexts. This study examined English stop voicing contrasts in the adult-directed and child-directed speech of 30 Singaporean early bilingual mothers who differed in their other language (Mandarin/Malay) and language dominance. Results showed that, while Malay and Chinese mothers used similar voice onset time (VOT) for voicing contrast, they differed in where on the VOT continuum these contrasts were made, regardless of speech style and dominance. Compared to their English-dominant peers, Malay/Mandarin-dominant mothers also produced smaller contrasts overall. These patterns could be attributed to cross-linguistic influence, as well as effects of long-term language contact and the mothers’ linguistic experiences. Sub-phonemic variation adds complexity to child bilingual phonological acquisition, emphasising the need to consider input properties in sociolinguistically complex contexts.

Supervised prediction of production patterns using machine learning algorithms

Abstract When an English word ending in a stop is adapted to Korean, a vowel is variably inserted after the final stop: some words always take the epenthetic vowel, and some never do, while some vary between these alternatives. Although there are different linguistic factors that possibly affect this insertion, it is not easy to determine which pattern will be chosen if a new word comes into the borrowing language. This study conducted classification data analyses of production patterns based on machine learning algorithms including support vector machines and random forests. These two classifiers show similar results where vowel tenseness is the best predictor among all the possible predictors. This indicates that vowel tenseness is most influential in classifying the patterns (no vowel insertion, optional vowel insertion, or vowel insertion). Results suggest that while vowel tenseness remains significant, other factors such as stop voicing and stop place also hold some importance, albeit to a lesser degree. The contribution of this study is that it provides insight into the factors that regulate vowel insertion, and these findings support the need for a behavioral experiment to see if the current results can make right predictions with respect to the behavior of nonce items.

The production of voicing in Namibian English stops by speakers of Khoekhoegowab

This study examines whether Namibian English spoken by L1 Khoekhoegowab speakers has word-initial stop voicing contrasts, and how they might be realized in freely produced speech. The data consists of English interviews collected from nine speakers of Namibian English. For analysis, a total of 365 words beginning with a stop-vowel sequence were extracted from the interviews, and analyzed for voice onset time (VOT). To examine the realization of voicing, the extracted words are divided into voiced and voiceless categories based on their phonological voicing in other varieties of English and their VOTs are compared statistically. The VOTs of voiceless stops are significantly longer than those of voiced stops. The results suggest a short-lag vs. aspiration contrast in word-initial stops in Namibian English and provide new information about the phonetic features of Namibian English consonants.

Production and perception of stop voicing in Central Australian Aboriginal English: A cross-generational study

ABSTRACT This paper reports on a series of studies investigating the production and perception of stop voicing contrasts in speakers of Central Australian Aboriginal English (CAAE; Alice Springs, Australia). Study 1 investigated Voice Onset Time (VOT) and Constriction Duration (CD) in stop consonants in naturalistic adult speech, and the speakers produced a VOT-based voicing distinction in word-initial stops, while medial voiceless stops differ from voiced stops in having both longer VOTs and longer CDs, at least for the syllable onset position. Study 2 investigated the implementation of stop voicing contrasts (VOT and CD) in a cohort of child CAAE speakers, and the results are consistent with the adult CAAE data, suggesting predictable intergenerational transmission. Finally, Study 3 tested child speakers’ perception of stop voicing contrasts using a mispronunciation detection task, where the participants demonstrated above-chance performance for the voicing distinction across all places of articulation. Together, the findings suggest that CAAE has phonemic stop voicing distinctions, like Mainstream Australian English, and that CAAE medial stops are jointly cued by both VOT and CD, a feature shared with the contact language, Kriol.

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.

Pre-fortis Clipping Patterns: A Cross Linguistic Examination of L2 English Production and Perception by Asian Learners of English

In English, it is widely observed that vowels are longer before voiced consonants than before voiceless ones such as English. However, in Mandarin Chinese, Vietnamese, Japanese, and Korean, the distribution of voiced-voiceless stop contrasts, and long-short vowel differences are vastly different from English. The purpose of this study is to determine whether these targeted learners’ L2 English production and perception change in terms of vowel duration as a function of stop voicing. The production measurements in the database of Asian learners revealed a distinct effect than the one observed in native speakers. There were no evident vowel lengthening patterns. The results of the perceptual experiment with 24 participants indicated that individuals tended to prefer voiceless stops when preceding vowels were shortened, but there was no statistically significant difference between intermediate, upper-intermediate, and advanced-level learners. However, learners demonstrated distinct perceptual patterns for various vowels and stops. The findings have valuable implications for L2 English speech acquisition.

Acoustic correlates of aspirated consonants in Maranao

Aspirated obstruents are rare in Austronesian languages, one exception being the southern Philippine language Maranao, as reported by Lobel and Riwarung [Oceanic Linguist. 48, 403–438 (2009)]. In Maranao, aspirated consonants occur as a reflex of a cluster of a former voiced stop and a homorganic obstruent (*bp > p’, *dt > t’, *ds > s’, *gk> k ’). The most obvious correlate to non-Maranao speakers is a dramatic raising of the following vowel, which also occurs after voiced obstruents, but not after historic single voiceless obstruents—e.g., /təkaw/ [təkaw] ‘startled’ (earlier *təkaw) vs. /tək’aw/ [təkʰɣw] ‘thief’ (earlier *təɡkaw) However, native Maranao speakers regard the raising as a property of the consonants, not the vowels. We examined the correlates of the apparent aspiration. The vowel raising is realized robustly and consistently, with some overlap in F1/F2 space among contrastive vowels. However, aspirated and unaspirated stops also show differences in VOT and in measures of breathiness of the following vowel, albeit with somewhat less consistency. Differences between /s/ and /s’/ were not evident except for realizations of following vowels. We explore the role of pharyngeal expansion due to voicing in the development of these Maranao segmental realizations.

도호쿠 일본어의 폐쇄음 지각에 있어서 voice onset time(VOT)과 후속모음 fundamental frequency(F0)의 역할*

Tohoku Japanese is known to have voiced stops without pre-voicing in word-initial position, whereas traditional or conservative Japanese has voiced stops with pre-voicing in the same position. One problem with this devoicing of voiced stops is that it affects the distinction between voiced and voiceless stops because their voice onset time (VOT) values overlap. Previous studies have confirmed that Tohoku speakers use post-stop fundamental frequency (F0) as an acoustic cue along with VOT to avoid overlap. However, the role of post-stop F0 as a perceptual cue in this region has barely been investigated. Therefore, this study explored the role of post-stop F0 in stop voicing perception along with VOT. Several perception tests were conducted using resynthesized stimuli, which were manipulated along a VOT continuum orthogonal to an F0 continuum. The results showed no significant regional difference (Tohoku vs. Chubu) for nonsense words (/ta-da/). However, for meaningful words (/pari/ ‘Paris’ vs. /bari/ ‘Bali,’ /piza/ ‘pizza’ vs. /biza/ ‘visa’), a significant word effect was found, and it was confirmed that some listeners utilized the post-stop F0 more consistently and steadily than others. Based on these results, we discuss innovative listeners who may lead the change in the perception of stop voicing.

The role of the tongue back on contrasting voicing properties of English coda consonants: Evidence from an ultrasound imaging technique

This study explores how voicing properties of stop consonants at the coda of a syllable are reflected in the articulation of the tongue back in American English. The association between the laryngeal control of the voicing property of consonants and the positioning of the tongue back has been increasingly reported (e.g., Ahn, 2018; Coretta, 2020). A recent study (Coretta, 2020) reported that longer vowel duration indicating the following voiced stop consonant corresponds to greater tongue root advancement at the offset of the vowel in Italian and Polish. Since the vowel with a following voiced stop consonant has a longer duration than that with a voiceless stop consonant, the later offset of TB movement should be correlated with the offset of vocal folds vibration in American English as well. The preliminary result suggests that the later offset of TB advancement is positively correlated with the longer vowel duration of voiced consonants at the coda of a syllable; therefore, contrasting voicing property of coda consonants in English is phonological and phonetically evidenced in the articulation of the tongue back. Articulatory data from ultrasound images of the tongue from three native speakers of American English will be presented.

Investigating the nature of speech representations by contrasting computational models against behavioral data

How do listeners interpret speech input when exposure does not contain information about the talker’s category representations? Competing accounts are rarely contrasted. We implement competing hypotheses within the same general computational framework (Bayesian inference). All models were trained on phonetic productions to predict perception, reflecting the hypothesis that listeners learn category representations from the speech input. We compare them against two experiments on the perception of L1-US English stop voicing (N = 24 and 122). Both experiments used minimal pairs (e.g., tin/din) varying in the primary cue (VOT) while keeping secondary cues (f0 and vowel duration) at expected correlations. VOT values occurred equally often and spanned the range observed in US English. We find that (1) models that integrated perceptual noise performed better in predicting categorization responses than those without; (2) models with multiple cues performed better than those with just VOT; (3) models trained on talker-normalized phonetic cues performed better than those trained on unnormalized cues; and, surprisingly, (4) models that also normalized the novel speech input during the experiment performed worse than those that did not. (3) and (4) suggest that listeners’ long-term representations are based on talker-normalized cues but require *labelled* input—contrary to most normalization accounts.

Acoustic prominence of verbal instructions in Parkinson's disease

Talkers signal important information to listeners in part by manipulating prosodic prominence. In English, this is typically achieved by producing more prominent words with greater durations, intensity, f0, and hyperarticulation, though this tendency may be reduced in talkers with motor speech disorders. In the present study, older adults with and without Parkinson’s disease (PD) and dysarthria engaged in a simple instructional game activity in which they directed a research confederate to move around pictures on a board. Utterances were designed to manipulate prominence on stop-initial monosyllabic target words that differed in onset voicing and following vowel quality. Non-prominent words were repeated in the spoken instructions (“Move the pot above the chair, now move the [pot] above the box”), while prominent words contrasted with a minimal pair differing in onset voicing (“Move the pot above the chair, now move the [bot] above the chair”). Eleven people with PD and 11 age- and gender-matched controls participated. Overall, prominent words were longer, louder, and higher pitched, though control speakers modulated f0 to a greater extent than talkers with PD. Both groups modulated the amount of voicing during closure but not VOT as a means of increasing stop voicing contrasts in prominent words.

Integration of fundamental frequency and voice-onset-time to voicing categorization: Listeners with normal hearing and bimodal hearing configurations.

This study investigates the integration of word-initial fundamental frequency (F0) and voice-onset-time (VOT) in stop voicing categorization for adult listeners with normal hearing (NH) and unilateral cochlear implant (CI) recipients utilizing a bimodal hearing configuration [CI + contralateral hearing aid (HA)]. Categorization was assessed for ten adults with NH and ten adult bimodal listeners, using synthesized consonant stimuli interpolating between /ba/ and /pa/ exemplars with five-step VOT and F0 conditions. All participants demonstrated the expected categorization pattern by reporting /ba/ for shorter VOTs and /pa/ for longer VOTs, with NH listeners showing more use of VOT as a voicing cue than CI listeners in general. When VOT becomes ambiguous between voiced and voiceless stops, NH users make more use of F0 as a cue to voicing than CI listeners, and CI listeners showed greater utilization of initial F0 during voicing identification in their bimodal (CI + HA) condition than in the CI-alone condition. The results demonstrate the adjunctive benefit of acoustic hearing from the non-implanted ear for listening conditions involving spectrotemporally complex stimuli. This finding may lead to the development of a clinically feasible perceptual weighting task that could inform clinicians about bimodal efficacy and the risk-benefit profile associated with bilateral CI recommendation.

Audiological and Demographic Factors that Impact the Precision of Speech Categorization in Cochlear Implant Users.

The ability to adapt to subtle variations in acoustic input is a necessary skill for successful speech perception. Cochlear implant (CI) users tend to show speech perception benefits from the maintenance of their residual acoustic hearing. However, previous studies often compare CI users in different listening conditions within-subjects (i.e., in their typical Acoustic + Electric configuration compared with Acoustic-only or Electric-only configurations) and comparisons among different groups of CI users do not always reflect an Acoustic + Electric benefit. Existing work suggests that CI users with residual acoustic hearing perform similarly to Electric-only listeners on phonetic voicing contrasts and unexpectedly poorer with fricative contrasts which have little energy in the range of the Acoustic + Electric listeners' acoustic hearing. To further investigate how residual acoustic hearing impacts sensitivity to phonetic ambiguity, we examined whether device configuration, age, and device experience influenced phonetic categorization in a large individual differences study. CI users with various device configurations (Electric-only N = 41; Acoustic + Electric N = 95) categorized tokens from five /b-p/ and five /s-ʃ/ minimal pair continua (e.g., bet-pet; sock-shock). We investigated age, device experience, and when applicable, residual acoustic hearing (pure tone hearing thresholds) as predictors of categorization. We also examined the relationship between phonetic categorization and clinical outcomes (CNC, AzBio) in a subset of our sample. Acoustic + Electric CI users were better able to categorize along the voicing contrast (steeper categorization slope) compared with Electric-only users, but there was no group-level difference for fricatives. There were differences within the subgroups for fricatives: bilateral users showed better categorization than unilateral users and bimodal users had better categorization than hybrid users. Age was a significant factor for voicing, while device experience was significant for fricatives. Critically, within the Acoustic + Electric group, hybrid CI users had shallower slopes than bimodal CI users. Our findings suggest residual acoustic hearing is beneficial for categorizing stop voicing, but not frication. Age impacts the categorization of voicing, while device experience matters for fricatives. For CI users with ipsilateral residual acoustic hearing, those with better hearing thresholds may be over-relying on their acoustic hearing rather than extracting as much information as possible from their CI, and thus have shallower fricative categorization.

Динамика фонетические межпоколенческих изменений глухости и звонкости смычных взрывных согласных в русской речи билингвов Германии

The article is devoted to the analysis of voiceless and voiced stop plosives’ realization in the speech of Russian-speaking children-bilinguals in Germany and their parents when reading a phonetically representative text aloud. The author measures the indicator of voice delay time relative to the moment of explosion in stop plosive consonants (voicing onset time — VOT) in bilingual children and their parents, as she considers it the most reliable acoustic indicator for distinguishing voiceless and voiced consonants. The phonetic categories of plosive stop consonants’ VOT differ in Russian and German, so VOT may be affected by interlingual phonetic interference.

Perceptual similarity is not all: online perception of English coda stops by Korean listeners

AbstractThis study examines conscious judgments of perceptual similarity between foreign and native structures, focusing on vowel epenthesis following coda stops in English nonwords borrowed into Korean. In a similarity judgment experiment, Korean listeners heard a triplet consisting of an English stop-final form and two Korean forms, one ending in a stop and one ending in stop-vowel; then they indicated which of the two Korean forms the English form sounded more similar to. This study investigated six different predictors: release, voicing and place of coda stop, vowel tenseness, final stress, and word length. Similarity judgment choices showed that Korean CVCV is judged as more similar to English CVC than Korean CVC when the English final stop is released or dorsal or when the English word is monosyllabic. Although this result confirms that stop release is indeed a major factor explaining vowel insertion in this context, no effects of stop voicing and vowel tenseness are not compatible with the perceptual similarity hypothesis, which is surprising since they have been previously argued to involve acoustic cues affecting L2 speech perception. These findings support the need for further research that concentrates more on direct perception rather than judgments of perceptual similarity.

Substantive bias and the positional extension of major place contrasts

The role of phonetic naturalness in biasing the learning of sound patterns remains an unsettled question in phonology. The present study investigates naturalness bias in phonotactic learning using a novel experimental paradigm that tests whether learners reproduce a phonetically-motivated phonotactic implicational about the distribution of major place contrasts in stops. Stops differing in place of articulation are easier to distinguish word-initially than word-finally, so place contrasts in word-final position should also exist in word-initial position. The reverse is not necessarily true. This implicational is typologically supported as well as motivated by perceptual naturalness. In two artificial grammar learning experiments, I exposed participants to place contrasts in stops either word-initially or word-finally and tested whether they extended the contrasts to the other word-edge position. Participants successfully learned to recognize novel words that fit the phonotactic pattern they had been trained on, but they were equally willing to extend the place contrasts in both directions, yielding no evidence for naturalness bias. These results contrast with those of a similar study that found asymmetric extension of the stop voicing contrast, supporting an effect of naturalness bias. Confusion data suggests that the reduction in perceptibility from word-initial to word-final position may be greater for stop voicing than for stop place of articulation. This difference may underlie the divergent results of the two studies, leading to the hypothesis that the strength of a substantive bias depends on the magnitude of its phonetic precursor.

The dual role of post-stop fundamental frequency in the production and perception of stops in Mandarin-English bilinguals

In non-tonal languages with a two-way laryngeal contrast, post-stop fundamental frequency (F0) tends to vary as a function of phonological voicing in stops, and listeners use it as a cue for stop voicing. In tonal languages, F0 is the most important acoustic correlate for tone, and listeners likewise rely heavily on F0 to differentiate tones. Given this ambiguity of F0 in its ability to signal phonological voicing and tone, how do speakers of a tonal language weight it in production and perception? Relatedly, do bilingual speakers of tonal and non-tonal languages use the same weights across different language contexts? To address these questions, the cross-linguistic performances from L1 (first language) Mandarin-L2 (second language) English bilinguals dominant in Mandarin in online production and perception experiments are compared. In the production experiment, the participant read aloud Mandarin and English monosyllabic words, the onsets of which typified their two-way laryngeal contrast. For the perception experiment, which utilized a forced-choice identification paradigm, both the English and Mandarin versions shared the same target audio stimuli, comprising monosyllables whose F0 contours were modeled after Mandarin Tone 1 and Tone 4, and whose onset was always a bilabial stop. The voice onset time of the bilabial stop and the onset F0 of the nucleus were manipulated orthogonally. The production results suggest that post-stop F0 following aspirated/voiceless stops was higher than that following unaspirated/voiced stops in both Mandarin and English production. However, the F0 difference in English was larger as compared to Mandarin, indicating that participants assigned more production weight to post-stop F0 in English than in Mandarin. On the perception side, participants used post-stop F0 as a cue in perceiving stops in both English and Mandarin, with higher post-stop F0 leading to more aspirated/voiceless responses, but they allocated more weight to post-stop F0 when interpreting audio stimuli as English words than as Mandarin words. Overall, these results argue for a dual function of F0 in cueing phonological voicing in stops and lexical tone across production and perception in Mandarin. Furthermore, they suggest that bilinguals are able to dynamically adjust even a secondary cue according to different language contexts.

The Acquisition of Italian Stops by Igbo Speakers

This research explored the acquisition of Italian singleton stops by Igbo speakers. The voiceless and voiced stop phonemes /p t k/ and /b d g/ are present in both Italian and in the Igbo languages. This creates a perfect condition to check the learning strategies implemented in Italian L2. The theoretical framework taken up in this study was the Speech Learning Model. According to this approach, the sounds of L2 can be perceived by learners as the same, similar or as new compared to those present in their L1, depending on the greater or lesser acoustic and perceptive distance established between them. A spectro-acoustic analysis achieved on the stops produced by Igbo learners of Italian showed the presence of sound categories with a different acoustic structure. In Italian L2 stops have undergone an important phonetic adaptation that makes them perceptually different from what is achieved by native Italians.

Construcción de mapas articulatorios para la detección automática de la enfermedad de Parkinson por medio de la voz

Background and objectivesRecent studies have shown that speech analysis provides relevant information to support the diagnosis and monitoring of patients suffering from Parkinson's disease (PD). In this work a methodology is proposed to create articulatory maps based on articulatory and phonological information such that allow a clear and interpretable visualization of the results. Materials and methodsA total of 100 speakers were recorded while reading a text with 36 words that includes all phonemes of the Colombian Spanish. Phonological features are extracted with two toolkits: PhonVoc and Phonet. Forced alignment is used to obtained the time-stamps per phoneme. Support vector machines and random forests are used to classify between PD patients and non-symptomatic subjects. ResultsAccuracies of up to 90% are observed when the phonological class «Vowels» is considered and also accuracies above 80% are found for «Nasals», «Voiceless ficatives» and «Voiced Stop». Articulatory maps are created based on Gaussian mixture models with the aim to enable the interpretation of results. ConclusionsThe proposed methodology is suitable for the automatic detection of PD and also to assess possible articulatory deficits in the production of specific phonological classes.

The rarity of intervocalic voicing of stops in Danish spontaneous speech

Previous studies of the phonetics of Danish stops have neglected closure voicing. Danish is an aspiration language, but the aspirated stops /p t k/ are produced with shorter closure duration and less articulatory effort than the unaspirated stops /b d ɡ/. Furthermore, all Danish stops are characterized by some degree of glottal spreading during the closure. In this study, we use a corpus of Danish spontaneous speech (DanPASS) to investigate the intervocalic voicing—its distribution across the two laryngeal categories, whether it patterns as a lenition phenomenon, and whether the aerodynamic environment predicts its distribution. We find that intervocalic voicing is not the norm for either set of stops and is particularly rare in /p t k/. Voiced tokens are mostly found in environments associated with lenition. We suggest that the glottal spreading gesture found in all Danish stops is a phonological mechanism blocking voicing, which is probabilistically lost in spontaneous speech. This predicts our results better than relying on laryngeal features like [voice] or [spread glottis]. The study fills a gap in our knowledge of Danish phonetics and phonology, and is also one of the most extensive corpus studies of intervocalic stop voicing in an ‘aspiration language.’