Vowel Production Research Articles

A comparison between tongue dorsum configurations during vowel production in hypernasal speech vs typical speech

Appropriate nasalization is important for intelligible speech production and can be impacted by various disorders, including a cleft palate. Nasalization is achieved primarily through coupling the nasal and oral cavities by opening the velopharyngeal (VP) port, which introduces a variety of acoustic features. Although VP control has the primary role in nasalization, evidence suggests articulatory changes such as lip rounding (constriction) enhances acoustic features of nasality, while a downward and forward movement of the tongue dorsum in high vowels could attenuate perceptions of nasality in individuals with competent VP function. There is yet scant evidence to indicate whether such systematic changes occur in the case of VP opening. In an attempt to further understand the clinical aspect of this concept, we evaluated the tongue height and forwardness using ultrasound in three speakers with VP insufficiency (VPI) and three speakers with typical VP function to investigate the tongue configuration across two conditions. Tongue dorsum excursion and tongue positioning index were captured using Assistive Articulation Assessment (AAA) software during the production of vowels /a/ and /i/ across VCV contexts. Further results will be discussed in the meeting.

Maintenance of phonological contrast in speech production of cochlear implant users

Prior work has shown that normal-hearing (NH) talkers produce more distinct vowels in words having a lower word frequency (WF) and higher neighborhood density (ND). Phonological contrast in speech production may differ between post-lingually deafened cochlear implant (CI) users and individuals with NH due to the degraded auditory input provided by CIs. The current study sought to determine whether the same pattern of vowel production exists in CI users. CI users were recorded reading monosyllabic words that were lexically “hard” (low WF, high ND) or “easy” (high WF, low ND). For each participant, vowel dispersion was calculated as the Euclidian distance from the center of the acoustic vowel space. If degraded acoustic input affects phonological contrast in CI users, we would not expect vowel dispersion to differ between vowels in “hard” and “easy” words, contrary to talkers with NH. Preliminary results revealed a significant effect of lexical difficulty on vowel dispersion, indicating that CI users produced more distinct vowels in “hard” words than in “easy” words. These preliminary findings could suggest that degraded auditory input does not substantially affect phonological contrast in vowel production in CI users, or that long-term adaptation to CI input can restore contrast after auditory deprivation.

Southern dialects of United States English and automatic speech recognition

Automatic Speech Recognition (ASR) technology is designed to provide more human to machine communication options. Emergent research has observed variant performance of ASR for African American English (AAE) and other minority dialects. Word prediction was observed to be better for AAE compared to majority dialects. The opposite was true for word identification accuracy. The researchers hypothesize the higher word error rate for AAE is related to phonetic factors of vowel duration, consonant production, rhythm, pitch, and syllable accent. This work evaluates that hypothesis. Recordings of two AAE and two White AE speaking women from North Carolina reading Comma Gets a Cure were submitted for transcription to the Microsoft ASR program. Several common transcription errors were noted across speaker groups with a greater variety of errors noted for the AAE women. Acoustic analyses of vowel duration, and the spectral acoustics of vowel and consonant production by talker and group will be completed. The results of this analysis will be useful to describing the specific aspects of AAE speech that may perturb the tested ASR. These data provide insight into the speech tasks and the sub and supra-segmental acoustic data that should be included in future ASR programming iterations.

Suitability of online and offline remote recording for vowel reduction analysis

Increasing demand for remote research techniques has led to several initial investigations of the suitability of remote recording for vowel production research. An initial consensus has emerged that remote recording may provide broadly accurate data for broad-strokes analysis, such as analyzing the relative positions of a speaker’s vowels, although some minor distortions may occur; fine-grained analysis of sociolinguistic variation suffers greatly from remote data collection (Freeman and De Decker, 2021). This study investigates the quality of data obtainable through two remote recording methods (online recording through Gorilla and offline recording via smartphone) for a vocalic phenomenon requiring a medium level of sensitivity of analysis, namely vowel reduction. Ten subjects completed a shadowing task eliciting target words containing one of five English vowels in reduced or unreduced form, taking simultaneous online and offline remote recordings. To determine whether the variability introduced through the remote recording process was sufficient to alter the findings of the study, results were compared to data from a second group of subjects who completed the task in person in a traditional laboratory setting. This comparison to in-person data allows for an assessment of the suitability of online and offline remote recordings for vowel reduction research.

A Study on the Perception and Production of Short Vowels e and ɛ of Korean Native Speakers and Indonesian Learners

Korean Journal of Applied Linguistics, 38/3, 95-127. This study was aimed at investigating the perception and production of short vowel /e/ and /ɛ/ of middle-age Korean native speakers and Indonesian intermediate and advanced learners, by conducting AX discrimination task and production task such as reading sentences composed of words containing /e/ and /ɛ/. The findings showed that middle-age native Korean speakers and all Indonesian Korean learners distinguished /e/ and /ɛ/ well. Unlike younger generations of Korean native speakers (Cho, 2002; Choi, 2003; Park, 2011; Shin, 2011; Yoon, 2011), middle-age native Korean speakers in this study recognize the difference between /e/ and /ɛ/. Conversely, middle-age native Korean speakers and Indonesian female intermediate and advanced learners were neutralizing /e/ and /ɛ/ when pronouncing them. In case of Indonesian learners do not distinguish the pronunciation of /e/ and /ɛ/, it presumably due to the absence of /3/ in the Indonesian vocal system. The implication of this study for Korean Language Education in Indonesia, is when teaching /e/ and /ɛ/, do not show only the phoneme itself or show them separately without attach with consonant. Hence the acoustic characteristics of those two phonemes can be expressed.

Learning on the Field: L2 Turkish Vowel Production by L1 American English-Speaking NGOs in Turkey

This study adopts the Speech Learning Model to investigate the first language (L1) influence as well as the effects of the length of residence and second language (L2) exposure on American English-speaking learners of Turkish in their productions of Turkish unrounded–rounded vowel pairs, with a particular focus on the vowel categories “new” to American English speakers (/y/, /œ/, and /ɯ/). L1 (English) and L2 (Turkish) speech samples were collected from 18 non-governmental organisation (NGO) workers. L2 experience was defined by whether the worker lived in an urban or regional environment in Turkey. Participants’ audio productions of the word list in L1 and L2 were segmented and annotated for succeeding acoustic analyses. The results show an interesting front–back variability in the realisations of the three vowels, including further back variants of the front vowels (/y/, /œ/) and more forward variants of the /ɯ/ vowel, with a substantial degree of interspeaker variability. While the analysis revealed no significant results for the length of residence, language experience was found to have a significant effect on the production of /y/ (F2) and /ɯ/ (F1/F2). This study forms a first step into the research of adult L2 acquisition in Turkish with a focus on L2 in the naturalistic workplace environment, rather than instructed settings. The findings of this study will contribute to the development of teaching materials for NGO workers learning Turkish as their L2.

Exposure to speech via foreign film and its effects on non-native vowel production and perception

This research presents two experiments that examine the effect of exposure to second language speech via foreign film on non-native speech production and perception. Experiment 1a investigated whether exposure to French film aided in the ability of naïve monolingual American English speakers to shadow French words containing high rounded vowels /y/ and /u/ as tested via acoustic analyses and native French listener perceptual judgements. Experiment 1b was a crosslinguistic perceptual assimilation task completed by the same participants, designed to explore the perception of rounded vowels /y/ and /u/, before and after film exposure. The results of Experiment 1a indicated that a single session of exposure to French film had a small, but significant, effect on shadowing of French /y/, which was also perceptible to native French listeners. Shadowing of /u/, however, was not significantly affected by exposure. Experiment 1b showed that participants did not alter the patterns of perceptual assimilation between the two French vowels and native English vowels following film exposure. We conclude that exposure to non-native speech via foreign film can affect some aspects of non-native speech development and hypothesize that further sessions may compound these initial benefits, especially in those who are already learning a second language.

Effects of Occupational Risk Factors on Subjective Vocal Aerodynamic Measures in Teachers.

Aerodynamics, vital to voice production forms an important correlate of voice. The study aimed to compare subjective vocal aerodynamic measures in teachers and nonteachers and verify the effects of a few known occupational risk factors on the voice of teachers. Group 1 consisted 264 female and 42 male teachers, teaching languages and/or core subjects for a minimum of 5years, between 30 and 45years from the local schools of the city and surrounding nine taluks. Group 2 had 100 female and 33 male nonteachers aged 30-45years. Audio-recordings were done individually during the midweek and in the middle of the day in a quiet environment at schools (school library) using portable digital audio recorder. Tasks: (a) Maximum Phonation time (MPT): maximum sustained productions of vowels /a/, /i/, /u/ and fricatives /s/, /z/ at comfortable pitch and loudness were noted in seconds, (b) s/z ratio computed from phonations of /s/ and /z/ sounds, and (c)Counts per Breath (CPB): counting of maximum numbers either in Kannada or English languages in a single breath. Results confirmed statistically significant increased mean values for all the measured parameters in male compared to the female participantsin both groups. However, Nonteachers showed better results in almost all measured parameters compared to the teachers. Effects of known ooccupational risk factors showed mixed results and the details are discussed.

Effects of airflow in constricted vocal tracts on vowel production of the reed-type artificial vocal fold

Effects of airflow in constricted vocal tracts on vowel production of the reed-type artificial vocal fold

Generational Phases: Toward the Low-Back Merger in Cooperstown, New York

This paper reports on a new sociolinguistic sample of Cooperstown, a village in rural central New York. Previous research suggested Cooperstown was losing the Northern Cities Shift (NCS) and acquiring the low back merger via koineization as a result of dialect contact among locally-born children of parents from other regions. The new data shows abrupt retreat from NCS patterns between the Baby Boom generation and Generation X. A “phase transition” pattern is observed in progress toward the low back merger: Millennial women are the first to describe low back minimal pairs as merged, despite no appreciable difference between Millennials and Generation X in production of the low back vowels. No evidence is found to support the hypothesis that koineization is responsible for these changes; it appears that Cooperstown is subject to the same trend away from NCS documented in many other communities, subject to many of the same constraints.

Perturbing the consistency of auditory feedback in speech.

Sensory information, including auditory feedback, is used by talkers to maintain fluent speech articulation. Current models of speech motor control posit that speakers continually adjust their motor commands based on discrepancies between the sensory predictions made by a forward model and the sensory consequences of their speech movements. Here, in two within-subject design experiments, we used a real-time formant manipulation system to explore how reliant speech articulation is on the accuracy or predictability of auditory feedback information. This involved introducing random formant perturbations during vowel production that varied systematically in their spatial location in formant space (Experiment 1) and temporal consistency (Experiment 2). Our results indicate that, on average, speakers’ responses to auditory feedback manipulations varied based on the relevance and degree of the error that was introduced in the various feedback conditions. In Experiment 1, speakers’ average production was not reliably influenced by random perturbations that were introduced every utterance to the first (F1) and second (F2) formants in various locations of formant space that had an overall average of 0 Hz. However, when perturbations were applied that had a mean of +100 Hz in F1 and −125 Hz in F2, speakers demonstrated reliable compensatory responses that reflected the average magnitude of the applied perturbations. In Experiment 2, speakers did not significantly compensate for perturbations of varying magnitudes that were held constant for one and three trials at a time. Speakers’ average productions did, however, significantly deviate from a control condition when perturbations were held constant for six trials. Within the context of these conditions, our findings provide evidence that the control of speech movements is, at least in part, dependent upon the reliability and stability of the sensory information that it receives over time.

3D Dynamic Spatiotemporal Atlas of the Vocal Tract during Consonant-Vowel Production from 2D Real Time MRI.

In this work, we address the problem of creating a 3D dynamic atlas of the vocal tract that captures the dynamics of the articulators in all three dimensions in order to create a global speaker model independent of speaker-specific characteristics. The core steps of the proposed method are the temporal alignment of the real-time MR images acquired in several sagittal planes and their combination with adaptive kernel regression. As a preprocessing step, a reference space was created to be used in order to remove anatomical information of the speakers and keep only the variability in speech production for the construction of the atlas. The adaptive kernel regression makes the choice of atlas time points independently of the time points of the frames that are used as an input for the construction. The evaluation of this atlas construction method was made by mapping two new speakers to the atlas and by checking how similar the resulting mapped images are. The use of the atlas helps in reducing subject variability. The results show that the use of the proposed atlas can capture the dynamic behavior of the articulators and is able to generalize the speech production process by creating a universal-speaker reference space.

The impact of orthographic forms on speech production and perception: An artificial vowel-learning study

This study investigates the effect of orthographic forms on phonetic aspects of isolated speech sound production and perception. Three groups of 25 L1-Spanish speakers were exposed to /y/ and /ɛ/ in a multi-session learning study. They heard the same vowels presented with: L1-incongruent orthographic forms, novel orthographic forms, or without orthographic forms. After three exposure sessions, participants were tested on vowel production in an elicited production task and vowel perception in a multiple forced choice task. All groups established new /y/ and /ɛ/ production and perception categories. Incongruent orthographic forms led to less target-like category positions for /y/ but not /ɛ/ in production and perception. Novel orthographic forms only facilitated more target-like perception for /y/. In a fourth session, Auditory-only participants were exposed to incongruent orthography for /y/ and novel orthography for /ɛ/. Sequential exposure to incongruent orthography caused less target-like production and perception category positions, while sequential exposure to novel orthography altered neither. Together these results suggest that orthographic forms affect isolated speech sounds and are encoded at the speech sound level. Incongruent grapheme-to-phoneme mappings from L1 to later-learned languages may critically affect the phonetic characteristics of non-native speech sounds, but learning outcomes depend on specific L1-L2 category contrasts.

Long-term Average Spectrum and Nasal Accelerometry in Sentences of Differing Nasality and Forward-Focused Vowel Productions Under Altered Auditory Feedback

To investigate whether voice focus adjustments can alter the audio-vocal feedback and consequently modulate speech/voice motor control. Speaking with a forward-focused voice was expected to enhance audio-vocal feedback and thus decrease the variability of vocal fundamental frequency (F0). Twenty-two healthy, untrained adults (10 males and 12 females) were requested to sustain vowel /a/ with their natural focus and a forward focus and to naturally read the nasal, oral, and mixed oral-nasal sentences in normal noise-masked auditory conditions. Meanwhile, a miniature accelerometer was externally attached on the noise to detect the nasal vibrations during vocalization. Audio recordings were made and analyzed using the long-term average spectrum (LTAS) and power spectral analysis of F0. Compared with naturally-focused vowel production and oral sentences, forward-focused vowel productions and nasal sentences both showed significant increases in nasal accelerometric amplitude and the spectral power within the range of 200∼300 Hz, and significantly decreased the F0 variability below 3 Hz, which has been reported to be associated with enhanced auditory feedback in our previous research. The auditory masking not only significantly increased the low-frequency F0 variability, but also significantly decreased the ratio of the spectral power within 200∼300 Hz to the power within 300∼1000 Hz for the vowel and sentence productions. Gender differences were found in the correlations between the degree of nasal coupling and F0 stability as well as in the LTAS characteristics in response to noise. Variations in nasal-oral acoustic coupling not only change the formant features of speech signals, but involuntarily influence the auditory feedback control of vocal fold vibrations. Speakers tend to show improved F0 stability in response to a forward-focused voice adjustment.

Egyptian vowel second formant in isolation and in transition following high-frequency fricatives by NLFC hearing aid in children: how does the pattern compare to typically hearing peers?

BackgroundHigh-frequency consonants form an area of difficulty among children with hearing impairment. Many technological setups have emerged in order to improve their audibility, among them nonlinear frequency compression (NLFC). Therefore, the following study was carried out in order to evaluate change in production of high-frequency fricatives by hearing-impaired children utilizing NLFC hearing aids. This was through spectrographic analysis of F2 onset of transition elicited by fricatives in a prevocalic context, and results were compared to typically developing (TD) children. A change in mid-frequency sounds due to high-frequency compression was also tested through production of sustained vowels in isolation.ResultsA preliminary prospective case-control study involved 9 patients with NLFC hearing aids, evaluated at 1- and at 6-month post-fitting, without receiving speech therapy. Spectrographic analysis of F2 formant onset in [a] and [i] vowels when combined with [s] and [f] fricatives in a CV (consonant-vowel) pattern, presented auditorily and audio-visually, was observed and analyzed. One patient was excluded due to noncompliance in attendance. In the 8 patients who completed the study, very high-frequency level of F2 onset in CV was notable in second versus first evaluation in NLFC group, to the extent of surpassing the typical value in TD control group with [i] vowel. Contrastingly, F2 of sustained vowels in isolation took a trend of a lower value after 6 months of NLFC hearing aid use, as compared to the first evaluation. Consequently, the gap between sustained vowel F2 level in TD and NLFC groups widened.ConclusionMean high-frequency range of F2 onset of transition in CV patterns of voiceless fricatives [s] and [f] with [i] and [a] vowels 6 months after NLFC fitting reflects an enhancement in the frequency range production of these sounds. A shift toward a lower F2 frequency range in sustained mid-frequency vowels, on the other hand, remains to be carefully investigated as a sequel of nonlinear frequency compression in the Egyptian hearing-impaired children.

Variability in L2 Vowel Production: Different Elicitation Methods Affect Individual Speakers Differently.

Elicitation methods are known to influence second language speech production. For teachers and language assessors, awareness of such effects is essential to accurate interpretations of testing outcomes. For speech researchers, understanding why one method gives better performance than another may yield insights into how second-language phonological knowledge is acquired, stored, and retrieved. Given these concerns, this investigation compared L2 vowel intelligibility on two elicitation tasks and determined the degree to which differences generalized across vowels, vowels in context, lexical items, and individual speakers. The dependent variable was the intelligibility of Cantonese speakers' productions of English /i I u ℧/ in varying phonetic environments. In a picture-naming task, the speakers produced responses without an auditory prompt. In a second task–interrupted repetition–they heard exemplars of the same targets without pictures, and repeated each one after counting aloud to 10, a step intended to disrupt their short-term auditory store and therefore prevent simple mimicry. For target words with scores below 80% on picture naming, mean intelligibility was more than 10 points higher on interrupted repetition. However, that difference did not generalize across conditions or across speakers. Thus, although it is technically accurate to say that, on average, interrupted repetition yielded better vowel intelligibility than did picture naming, that observation requires a great deal of qualification, particularly because of individual speaker differences. The outcomes are interpreted in terms of their relevance to language assessment and phonetic learning.

Vowel Perception and Production in Native ki-Swahili Speaking Children Acquiring English as a Foreign Language

Abstract This study investigated the perception and production of English unrounded vowel minimal pairs /ɑ/ – /ɜ/; /æ/ – /ɑ/ and /i/ – /ɪ/, by a group of twenty native ki-Swahili speaking children averaging 9.9 years of age, who learned English through classroom instruction. The study was conducted in a typical foreign language acquisition (FLA) context. All the children participated in vowel perception and production tests. The findings revealed that the participants relied on their first language (L1) phonetic contrast knowledge when encoding vowel contrast. Moreover, factors that contributed to this problem of vowel contrast encoding included the size of the speakers’ vowel inventory, their limited exposure to spheres for interacting with the language outside the classroom environment and their social setting. Although the participants in this study demonstrated better ability in their vowel production than in their vowel perception, the results confirm those challenges that have been associated with FLA perceptual studies and how a young speaker’s first language significantly influences the child’s acquisition of English.

Vowel sound production and its association with cephalometric characteristics in skeletal Class III subjects.

This study aimed to evaluate differences in vowel production using acoustic analysis in skeletal Class III and Class I Japanese participants and to identify the correlation between vowel sounds and cephalometric variables in skeletal Class III subjects. Japanese males with skeletal Class III (ANB < 0°) and Class I skeletal anatomy (0.62° < ANB < 5.94°) were recruited (n = 18/group). Acoustic analysis of vowel sounds and cephalometric analysis of lateral cephalograms were performed. For sound analysis, an isolated Japanese vowel (/a/,/i/,/u/,/e/,/o/) pattern was recorded. Praat software was used to extract acoustic parameters such as fundamental frequency (F0) and the first four formants (F1, F2, F3, and F4). The formant graph area was calculated. Cephalometric values were obtained using ImageJ. Correlations between acoustic and cephalometric variables in skeletal Class III subjects were then investigated. Skeletal Class III subjects exhibited significantly higher/o/F2 and lower/o/F4 values. Mandibular length, SNB, and overjet of Class III subjects were moderately negatively correlated with acoustic variables. This study did not take into account vertical skeletal patterns and tissue movements during sound production. Skeletal Class III males produced different /o/ (back and rounded vowel), possibly owing to their anatomical positions or adaptive changes. Vowel production was moderately associated with cephalometric characteristics of Class III subjects. Thus, changes in speech after orthognathic surgery may be expected. A multidisciplinary team approach that included the input of a speech pathologist would be useful.

Acoustic Cues of /ħ/ and /ʕ/ in Hourani Jordanian Arabic: Investigating Sociolinguistic Variation

This paper examines the interaction between the coarticulatory effects of pharyngeals on adjacent vowels and the speakers’ age and gender in Hourani Jordanian Arabic. To this end, 28 participants were recorded reading a list of 24 words containing a pharyngeal sound (/ħ/ or /ʕ/) preceded (word-finally) or followed (word-initially) by a short or long vowel. A total of 1344 tokens were extracted and then analyzed in PRAAT. The first three formant frequencies (F1, F2, F3) of each vowel were manually measured at the midpoint. The measurements were then normalized using Nearey’s (1977) intrinsic formula to reduce the effect of physiological differences between male and female speakers. The findings of the study show no significant effects of age or gender on the production of the adjacent vowels word-initially or word-finally. This suggests that, unlike the case of pharyngealized sounds (e.g., Omari and Jaber (2019)), pharyngeal-to-vowel coarticulation is not affected by the sociolinguistic variables of age and gender. Keywords: Coarticulation; Extralinguistic variables; Hourani Jordanian Arabic; Pharyngeals.

Valores de nasalancia para vocales, serie numérica y oraciones producidas por adultos hablantes de español chileno

ObjectiveThe present study aimed to establish and compare nasalance scores in Spanish-speaking adults of both genders from Chile during the production of sustained vowels, an automatic speech sample and the reading of sentences. Methods46 adults participated, 25 women and 21 men, aged between 18 and 29 years. All without a history of speech therapy, neurological pathologies, intellectual deficit, hearing loss, syndromes or other pathologies that affect speech production. Adequate velopharyngeal function was determined in vivo through a perceptual evaluation of resonance. Nasalance was determined with the Nasometer, model 6450, during the sustained production of the vowels /a/, /i/ and /u/, an automatic repetition of the number series 1-10 and the reading of six sentences, five with consonants high pressure orals and one with nasal consonants. The comparison between both genders was made with the Mann-Whitney U test. ResultsThe sentence with nasal sounds («Mi mamá me mima») presented the highest percentage of nasalance with 66.36%, followed by the numerical series with 24.61% and the vowel /i/ with 23.57%. Meanwhile, sentences with oral sounds and sustained vowels /a/ and /u/ presented an average nasalance that fluctuated between 10.5% (vowel /u/) and 16.52% (sentence: «Fifi fue feliz»). Finally, a significantly higher average was observed in women for three oral sentences: «Pipo patea la pelota» (P=.044), «Tito tapa tarros» (P=.041), and «Fifi fue feliz» (P=.027). ConclusionThe nasalance values obtained in Chilean adults showed variations according to the speech stimulus and the gender of the speakers.