Vowel Production Research Articles

Acoustic Effects of Speaker Sex, Speech Sample, and Mandarin Tone on Vowel Production of Poststroke Spastic Dysarthria

Plain Language SummaryMandarin speakers with poststroke spastic dysarthria often have vowel production deficits that affect articulation and speech intelligibility. Vowel production is influenced by many factors. This study explored the acoustic effects of speaker sex, tones, and speech samples and their interactions on vowel production in Mandarin speakers with poststroke spastic dysarthria and confirmed the existence of these effects. We found that regardless of the speech samples or tones, there were the reduced range of articulatory movements, centralized vowel production, and prolonged vowel duration in dysarthria compared to healthy people. The most sensitive and useful analysis measures were the vowel articulation index and vowel duration. Specific influencing factors (speaker sex, speech sample, and tone) of vowel production need to be taken seriously by speech and language pathologists and considered in the assessment and rehabilitation.

Unexpected findings from L2 speech research can help us understand how humans process vowels

Research on nonnative speakers’ vowel production and perception has provided us with a number of surprising insights on how learners cope with nonnative vowels. Three of these initially unexpected, yet later solidly replicated, findings will be presented: (1) A decline in intelligibility of nonnative vowels as general proficiency improves (when an increase in intelligibility will be expected), (2) the use of acoustic cues in L2 vowel perception that cannot be attributed to transfer from the native language, and that are nonfunctional in the L2, and (3) the maintenance from infant speech perception in adult cross-language vowel perception of a bias favoring peripheral vowels. This presentation will discuss implications of these findings for our understanding of how vowel categories coexist in the minds of multilinguals, and of universally (native-language independent) preferred ways of vowel perception.

Predicting vocal tract shape information from tongue contours and audio using neural networks

Midsagittal ultrasound imaging of the tongue is a portable and inexpensive way to provide articulatory information. However, although ultrasound images show a portion of the tongue surface, other vocal tract structures (e.g., palate) are not typically visible. This missing information may be useful for speech therapy and other applications, e.g., by characterizing vocal tract constrictions and informing how morphological variations affect speech patterns. Prediction of the vocal tract shape from information available during ultrasound imaging (e.g., tongue contours and audio recordings) is, thus, potentially valuable. Recent advancements in articulatory prediction from audio recordings (i.e., acoustic inversion) and speech recognition using combined articulatory and acoustic data have used neural network models. Inspired by these models, this study investigates how well fusion of articulatory and acoustic features in speaker-independent models can predict expanded articulatory information. Specifically, recurrent neural network models will be trained to predict the vocal tract shape based on partial tongue contours and acoustic features, during production of vowels and central approximants. Features will be extracted from simultaneously recorded audio and 2D MRI (USC 75-Speaker Database). Different acoustic features and network architectures will be compared, with the goal of refining future models to predict vocal tract shapes during ultrasound imaging.

Modeling vowel-inherent spectral change in varying consonant context

A wide variety of experimental evidence has shown that vowel inherent spectral change (VISC) is important in vowel identification. This evidence is drawn from production data, statistical pattern recognition, and perceptual experiments with both synthetic or manipulated naturally produced speech. Experimental studies often consider vowels in a constant consonant context which makes it difficult to factor out context effects from the VISC itself. In order to examine the magnitude of these consonant effects, we developed a statistical procedure inspired by Broad and Clermont [(2014). J. Phon. 47, 47–80] in which vowel formant frequencies are approximated by a linear combination of vowel and consonant influences which vary as a function of time. Vowels extracted from a database of both spontaneous and read speech were analyzed to produce context-normalized vowel-formant tracks. Results show that vowel formant frequencies vary systematically across their duration in both spontaneous and read speech and that all consonants in both onset and coda position show significant effects on vowel production across their entire duration. Although these formant patterns are seemingly complex, perceptual evidence suggests that listeners may only attend to onsets and offsets and that deviations from a straight-line interpolation between onset and offset must be relatively large for listeners to discriminate them.

The effect of aging on vowel production in Western Canadian English

Aging influences many aspects of speech production. For example, a speaker’s fundamental frequency or formant space has been reported to change as they age. However, this research has largely focused on careful or prepared speech, with a few notable exceptions in the longitudinal research literature. There is limited knowledge of the relationship between aging and vowel reduction in spontaneously produced speech. It is important to investigate how spontaneous everyday speech is influenced by the aging process. In the present investigation, we work with a corpus of Western Canadian English containing spontaneous conversational speech produced by 18 younger (17–31) and 13 older speakers (64–79). The data was force-aligned and then acoustic measures were extracted from the aligned data. In this presentation, we report on the differences in formant space for stressed and unstressed vowels. The results of this study will be used to better inform our understanding of the role of vowel centralization and aging in spontaneous speech. They will further support the understanding of reduction in spontaneous speech.

What babies bring to our understanding of vowel perception

Vowels are produced and perceived very early in infancy and occupy a central role in speech communication across the lifespan. Many phenomena first uncovered in vowel research with adults were later explored with infants. This produced important findings that inform our understanding of vowel perception and production development. In this talk, I will highlight several perception findings that were initially discovered in infants which now also direct fruitful lines of research with adults. I will focus on two perceptual biases—the focal vowel bias and the infant talker bias—each involving information conveyed by vowels. The focal vowel bias identifies a universal vowel perception bias that is germane across the lifespan. Elaborating the mechanism(s) behind this bias can lead us to a more principled understanding of basic vowel perception processes. The infant talker bias – first identified in infants and now also in adults – reveals a robust bias favoring infant conspecific vocalizations. This bias appears to impact infant development directly and also indirectly via its’ positive effect on parenting behaviors. Going forward, the interplay of research across age groups will continue to bring us a deeper understanding and appreciation of the ubiquitous role of vowels in human cognition.

Speech adaptation in conversation: Effects of segment cue-weighting strategy for non-native speakers

Research has investigated how speakers make phonetic adaptations by adjusting their speech sounds to either converge to or diverge from their interlocutor’s. Less is known about the dynamic adaptive strategies non-native speakers use to improve intelligibility when interacting with native speakers, particularly how their strategies change over the course of spontaneous conversations. The current study examines phonetic adaptations in English words contrasting tense and lax vowels (e.g., sheep-ship) in unscripted conversations between non-native Japanese English and native English speakers during an engaging computer game task. Japanese speakers have previously been found to rely on temporal cues (vowel length) for tensity distinctions due to their L1 cue-weighting strategy rather than spectral cues (vowel quality) that are predominantly used in English. Acoustic analyses are conducted to examine changes in non-native vowel productions before, during and after the conversation task. We predict that, in an attempt to overcome miscommunication, non-native speakers may initially lengthen the tense vowels to distinguish them from their lax counterparts. As the conversation progresses, non-native speakers may adapt to a more native-like cue-weighting pattern by shifting to spectral distinctions. Results are discussed in terms of adaptations to cue-weighting strategies for intelligibility gains by interlocutors of different linguistic backgrounds.

Acoustics and ice hockey: The sociophonetic impact of Canadian English on American-Born players

My research utilizes sociophonetic analysis to document the linguistic identity construction process that is ongoing in the sport of ice hockey. I argue that American-born players are constructing a hockey-based identity influenced by Canadian English (CE) due to the historical Canadian dominance of the sport. This identity incorporates Canadian Raising, FACE and GOAT monophthongization, both commonly attributed to CE and largely unexplainable based on players’ regional dialects, and altered vowel production in hockey-specific terminology, most notably in the word hockey itself, unique to the hockey community. To document this variation, I analyze vowel formant values taken from sociolinguistic interviews with professional hockey players. I assess F1 and F2 values throughout vowel durations to establish if players are converging in production away from regional dialectal variants towards shared hockey-based variants. I argue these variants have gained indexical value linked to an emerging hockey-based identity that, although influenced by CE, is unique to the hockey community. In ongoing research, I aim to further document that this variation is most evident in hockey-specific terminology and that lexical diffusion occurs outwardly from these terms over time leading to players developing a more prevalent hockey-based identity as the sport gains more importance in their lives.

Revisiting the sociophonetics of sexuality in spontaneous speech

This study surveys sociophonetic variation in sibilant and vowel production for 44 Bay Area English speakers. I focus on (i) whether sexual orientation is an independent predictor, or interacts with gender, and (ii) what the patterning of bi + (bisexual, pansexual, queer, etc.) and non-binary speakers adds to previous claims (e.g., Gaudio 1994, Pierrehumbert 2004, Willis 2023). All participants completed a Map Task in pairs; 37 participated in a sociolinguistic interview. Recordings were auto-transcribed, forced-aligned, and hand-checked. For /s ʃ z ʒ/, tokens under 0.05 sec, in /str/ clusters, and/or adjacent to another sibilant were excluded. Before getting COG and skew, 0.02 sec were subtracted from token edges and voicing was Hann band-filtered. For all vowels and sibilants, mean and midpoint f0 were taken, and F1-F4 for vowels (using the median of values at midpoint plus six surrounding timepoints). Results show sexual orientation alone is not a robust predictor of /s/ frontedness. Both gender and sexuality interacted with duration for /s/ frontedness and vowel f0; gender and sexuality also interacted to influence /ʃ/ frontedness and /z/ devoicing, as well as vowel space shape. These results imply that, when bi + and non-binary identities are incorporated, the phonetic indexation of sexual identity is not easily generalizable within orientation labels, at least for informal speech.

The Effects of Orthography on the Pronunciation of Nasal Vowels by L1 Japanese Learners of L3 French: Evidence from a Longitudinal Study of Speech in Interaction

In recent decades, a vast literature has documented crosslinguistic influences on the acquisition of L2 phonology and in particular the effects of spelling on pronunciation. However, articulating these research findings in terms of taking into account the effects of L1 phonology and spelling on L2 pronunciation in language teaching remains to be examined. These studies are based on experimental cross-sectional methods and mainly focus on L2 English learning by speakers of languages with an alphabetic system. In French, there are few studies on crosslinguistic influences on the acquisition of the nasal vowels (/ɑ~/, /ↄ~/ and /ε~/) and few experimental studies that point to a possible effect of orthography on the pronunciation of these phonemes. The results of experimental studies are difficult to transpose to the language classroom because they are based on word or sentence reading and writing activities, which are quite far-removed from the conversational activities practised in the classroom in interaction with peers and the teacher. Hence, we opted here for a case study of the effect of spelling on the production of nasal vowels in interaction tasks. We conducted a longitudinal study during the first year of extensive learning of French (4 hrs 30 per week). The results of a perceptive analysis by expert listeners show that (i) learners spell nasal vowels with an <n> or <m> in 98% of the obligatory contexts; (ii) most nasal vowels are perceived as nasal vowels in speech (72%), the others being perceived as vowels followed by a nasal consonant (19, 5%) or as oral vowels (8.5%); (iii) consonantisation is stronger when the learner spontaneously produces a word than when (s)he repeats it, (iv) which decreases with time (learning effect) and varies (v) according to the consonant, /ε~/ being less consonantised than /ↄ~/ and /ɑ~/. Finaly, we propose a didactic discussion in the light of intelligibility and influence of orthography.

ОБ ОПЫТЕ ИСПОЛЬЗОВАНИЯ МУЛЬТИМЕДИЙНЫХ СРЕДСТВ В ОБУЧЕНИИ ФОНЕТИКЕ РУССКОГО ЯЗЫКА КАК ИНОСТРАННОГО (НА ПРИМЕРЕ ВОЛГГМУ)

A necessary condition for the development of communication skills and abilities in a foreign audience is mastering the skills of correct pronunciation. Foreign students are going to communicate with native speakers, and also receive higher professional education in Russian language. Work on the production of any sound of Russian language is preceded by the development of phonemic hearing: students need to learn to distinguish and recognize Russian phonemes by ear. This research is devoted to the analysis of the techniques and methods available in the methodology for teaching phonetics of the Russian language to foreign students of non-linguistic universities from different countries at the present time. The features of the production of vowel and consonant sounds that cause special difficulties for students are considered. Particular attention is paid to modern multimedia tools and online resources that contribute to the successful mastery of the phonetic structure of the Russian language by foreign students. The author proves the need to use interactive exercises to create sounds and overcome difficulties associated with pronunciation. In addition, examples of specific exercises for introducing, training and consolidating phonetic material are given. This article can serve as a practical basis for methodological recommendations to lecturers of Russian as a foreign language in the process of teaching foreign students both in introductory phonetic and accompanying phonetics courses.

Vowel articulation and intelligibility of speech in Spanish speakers with Parkinson's disease treated with deep brain stimulation of the subthalamic nucleus

Parkinson's disease (PD) can affect the intelligibility of speech. Although studies of vowel production are useful for measuring this impairment, they do not exist in Spanish speakers with the disease who have been treated with subthalamic nucleus deep brain stimulation (STN-DBS). STN-DBS is an effective treatment for the classic signs of PD, but with varied effects on speech. Data from two individuals with PD treated with STN-DBS were studied: one (P1) had impairment and the other (P2) had stable speech intelligibility after STN-DBS implantation. The triangular vowel space area (tVSA) and the vowel articulation index (VAI) were measured and compared before the implantation surgery, and at three, six and nine months after surgery. These measurements were compared with measurements of speech intelligibility (percentage of words correctly identified and degree of intelligibility). Both participants presented variations in measurements of vowel articulation after surgery. In P1, the reduction in the tVSA, but not the post-surgical change in the VAI, was consistent with reduced speech intelligibility. However, in P2, both measurements (tVSA and VAI) reflected stable speech intelligibility after surgery. Reduced speech intelligibility in Spanish speakers with PD after STN-DBS implantation may be reflected in a reduced tVSA.

Production of English Vowel Contrasts in Spanish L1 Learners: A Longitudinal Study

The present study undertakes a longitudinal examination of forty postgraduate students, native Spanish speakers, during their first year at a UK university. The research focuses on both individual and collective progress in mastering distinctions within English vowel pairs (/iː/-/ɪ/, /ɪ/-/e/, and /uː/-/ʊ/), with a specific focus on adaptations towards achieving native-like English vowel pronunciation, particularly in terms of vowel quality. Prior research indicates that adult Spanish learners encounter difficulties in mastering the intricate linguistic nuances presented by English. The methodology involved recording Spanish-speaking participants reading a list of words (CVC context) at three different time points over a year. The analysis was based on formant frequencies using Praat, and Euclidean distances were calculated to represent the degree of separation between each pair of vowels. Information about external factors potentially influencing the development of vowel productions among speakers was gathered through a language background questionnaire. The outcomes suggested varying rates of advancement within the group, which could be attributed to the diverse levels of exposure and interaction with native English speakers during their year of study in the UK. These results affirm the learning processes in adult L2 production, emphasizing the critical role played by both the quantity and quality of time in the assimilation of pronunciations to novel L2 segments.

Understanding the Difficulties of Saraiki Speakers with English Vowel Pronunciation at Secondary Level

English language is an international language, as for as the pronunciation of English vowels is concerned, the learners of L2 face a lot of problems. It’s believed that Pakistani students especially Saraiki students face colossal difficulties in the production of English vowels and face a lot of problems in the recognition of English vowel sounds because of the improper guidance by the teachers as well as the influence of mother tongue. Pakistani Institutions neglect the importance of pronunciation. The researcher conducted research in district Multan (Pakistan) and from Multan city, she selected fifty students of 9th and 10th class from five different Govt. and Private high schools. From each school ten students were selected and female students from four different schools and male students from one school were selected. A list of one hundred and sixty words was prepared and these words were pronounced by the students. Data was recorded in a C.D and analysed in percentage. Findings showed that there was a lack of teachers’ training as well as improper guidance to the students by teachers and the surroundings. This study suggested some ways for improving pronunciation of English vowels and at the end conclusion was drawn.

Perception and production of French oral vowels by Japanese-speaking learners: does dialectal variation play a role?

This paper presents a series of studies on the impact of regional variation in L1 (source language) on L2 (target language) pronunciation, focusing on the high back vowel /u/ in French perceived or produced by native speakers of Japanese from the Kanto area (around Tokyo) and the Kansai area (around Osaka). 1) To serve as a base line, the 5 Japanese vowels were pronounced by 11 speakers (5 women and 6 men) from Kansai with no learning experience of French and their first 4 formants were measured to examine their acoustic properties. 2) 25 naïve listeners from Kansai took part in an AXB auditory discrimination task for French vowels including pairs /u/-/y/, /y/-/ø/ and /u/-/ø/; the results were compared with those of Kanto speakers in previous studies. 3) Some Japanese-speaking learners of French (JSL) from Kansai produced the French /u/ with a lower F2 (around 1,000 Hz for men) than typical values observed for learners from the Tokyo area. These results show limited differences for some of the speakers from Kansai compared to the tendency commonly observed with Kanto speakers

The overlooked effect of amplitude on within-speaker vowel variation

Abstract We analyse variation in vowel production within monologues produced by speakers in a quiet, well-controlled environment. Using principal component analysis (PCA) and generalized additive mixed models (GAMMs), applied to a large corpus of naturalistic recordings of New Zealand English speakers, we show that the first formant of monophthongs varies significantly with variation in a speaker’s relative amplitude. We also find that amplitude variation is used, potentially agentively, to mark the beginning and ending of topical sections within single-speaker monologues. These results have significant methodological consequences for the study of vocalic variation in the context of research on speaker style and language variation and change. While laboratory research has shown a connection between variation in F1 and amplitude in loud environments or with distant interlocutors, this has not been seen in quiet environments with unscripted speech of the sort often used in sociolinguistcs. We argue that taking account of this variation is an important challenge for both within-speaker investigation of stylistic covariation and across-speaker investigation. In the latter case we recommend, as a minimal step, the inclusion of a measure of relative amplitude within regression models.

Acoustic adjustments of clear speech in Korean heritage vowel production

Aims and objectives: This study aims to explore the segmental and suprasegmental acoustic adjustments in the clear speech of Korean vowels produced by English-dominant Korean-heritage speakers and native Korean speakers. Methodology: Native Korean students at a university in the United States and Korean-American students enrolled in an intermediate Korean language course at the same university read isolated sentences featuring three representative Korean vowels (i.e., /i, a, u/), once in casual speech, and once in clear speech. They repeated this sequence five times. Data and analysis: The vowel space of the first and second formants (F1 and F2) in the clear speech was expanded for both heritage and native speakers, and the heritage vowel space was more fronted than the native vowel space, suggesting the influence of English among heritage speakers. However, the peripheral extent and direction in the clear speech and the dominant language effect in heritage speakers were inconsistent across the vowels. Also, pitch dynamics were highly significant in clear speech, exhibiting the salient fundamental frequency (F0) rising at the syllable offset for both heritage and native speakers. The vowel length enhancement in the clear speech was also confirmed in both native and heritage Korean vowels. Conclusions: The results confirmed the cross-language tendency in clear speech to induce the modification of vowel quality, pitch, and duration, which also applies to Korean heritage vowel production. Furthermore, the asymmetrical acoustic modifications across the vowels in heritage clear speech support the Speech Learning Model (SLM) prediction. Originality and implications: The findings present new data for the clear speech effects of Korean heritage vowel production and a further enhancement strategy of syllable offset pitch raising in clear speech for both native and heritage groups. The results contribute to the theoretical implication of bilingualism by connecting the SLM premise and heritage clear speech.

How do I sound? Vowel production of multilingual students at Ma Chung University

This study aims to evaluate the Indonesian, English, and Mandarin vowel production of Ma Chung University students, a prominent Indonesian institution with a strong emphasis on workforce readiness. Given the university's language offerings encompassing Indonesian, English, and Mandarin, we employed a descriptive qualitative approach in acoustic-phonetic theory. Our respondent pool comprised of 15 PPBM (Chinese language major) students selected based on intermediate proficiency levels in all three languages, as indicated by TOEIC and HSK scores. First and second formant data for monophthongs were recorded in PRAAT tools and the data is compiled on Microsoft Excel, forming the foundation for Vowel Space Area (VSA). The data reveals a notable phenomenon: students' native language (Indonesian) influences their pronunciation of both the second (English) and third (Mandarin) languages. Particularly, English displays a distinct pattern of compressed vowel spread compared to the standard VSA table due to the lingering impact of L1 VSA. This effect accounts for observed vowel anomalies in student pronunciation. Importantly, this L1 and L2 influence is evident in their attempts to articulate L3 (Mandarin) sounds, exemplified by the significant deviation of /ə/ from the VSA. Moreover, students navigate a linguistic shift by modifying phonemes to align with their L1, inadvertently resulting in substantial deviations during English and Mandarin speech production.

Premotor cortex is hypoactive during sustained vowel production in individuals with Parkinson's disease and hypophonia.

Hypophonia is a common feature of Parkinson's disease (PD); however, the contribution of motor cortical activity to reduced phonatory scaling in PD is still not clear. In this study, we employed a sustained vowel production task during functional magnetic resonance imaging to compare brain activity between individuals with PD and hypophonia and an older healthy control (OHC) group. When comparing vowel production versus rest, the PD group showed fewer regions with significant BOLD activity compared to OHCs. Within the motor cortices, both OHC and PD groups showed bilateral activation of the laryngeal/phonatory area (LPA) of the primary motor cortex as well as activation of the supplementary motor area. The OHC group also recruited additional activity in the bilateral trunk motor area and right dorsal premotor cortex (PMd). A voxel-wise comparison of PD and HC groups showed that activity in right PMd was significantly lower in the PD group compared to OHC (p < 0.001, uncorrected). Right PMd activity was positively correlated with maximum phonation time in the PD group and negatively correlated with perceptual severity ratings of loudness and pitch. Our findings suggest that hypoactivation of PMd may be associated with abnormal phonatory control in PD.

The role of auditory processing in L2 vowel learning: evidence from recasts

Developing adequate second language (L2) speech has increasingly become one of the important goals in today’s globalized world. The current study set out to investigate how the provision of recasts can facilitate English vowels /i/-/ɪ/ learning by Chinese native speakers and how such learning gains resulting from recasts can be tied to individual differences in auditory processing. An experimental group of thirty young adults was engaged in ten treatment sessions of recasts lasting ninety minutes each to notice and practice English vowels /i/-/ɪ/. Their learning gains were tested through a forced-choice identification task, a controlled word-reading task, and a spontaneous picture-narrative task before and after receiving recasts. A control group of the same number of participants was also included to receive comparable sessions without receiving any recasts to check for test-retest effects. Quantitative analysis showed that recasts significantly helped Chinese native speakers facilitate their learning of English vowels /i/-/ɪ/ regardless of time and lexical context. Such learning gains resulting from recasts were significantly correlated with specific constructs of auditory processing. Namely, perceptual acuity was significantly correlated with gains from recasts in identifying L2 vowels, and audio-motor integration with gains from recasts in controlled/spontaneous production of L2 vowels. The findings suggest that recasts can serve as ideal instructional techniques of L2 vowel learning for Chinese native speakers and that the auditory processing profiles of individuals can suggest how they can benefit the most from recasts.