Vowel Space Area Research Articles

Acoustic characteristics of tense and lax vowels across sentence position in clear speech

This study examines how the inherent properties of tense and lax vowels interact with external factors, such as speech style (clear vs conversational) and position (sentence-medial vs sentence-final). Twelve speakers of American English recorded productions of the tense /i,u,ɑ/ and lax /ɪ,ɛ,æ,ʊ,ʌ/ vowels, all of which were lengthened and decentralized to a similar degree in clear speech. Furthermore, unlike tense vowels, lax vowels had a greater vowel space area in sentence-medial position, which was primarily driven by high vowels' decreased F1. Therefore, the defining properties of lax vowels (short duration and centralization) were altered by both speech style and sentential position.

Diphthong productions in speakers with Parkinson’s disease across speaking modes

Several vowel acoustics parameters (e.g., second formant frequency (F2) slope, vowel space area) are known to significantly contribute to speech intelligibility in dysarthria (Kim, Kent, Weismer, 2011; Lansford & Liss, 2014). Particularly, F2 slope has been identified as an important predictor of speech intelligibility regardless of underlying neuropathologies of dysarthria (Kim, Weismer, Kent & Duffy, 2009). The current study focuses on intra-speaker modifications of F2 slope in speakers with Parkinson’s disease (PD) voluntarily elicited across three speaking modes, less clear, conversational, and more clear speech, in recognition that prior work has mostly focused on inter-speaker comparisons. Varying speech clarity was our interest, given its wide use as an efficient behavioral therapeutic approach in clinic. Twenty speakers (10 PD, 10 neurologically healthy) were asked to read diphthongs embedded in real words. Diphthongs were chosen because they require a significant change in configuration of vocal tract and, therefore, are sensitive to the presence/severity of dysarthria. In the presentation, distributions of F2 slope 1) between PD and healthy speakers, and 2) across speaking modes within each speaker will be discussed. In addition, articulatory data will be presented for part of the speakers from whom kinematic data were obtained using the electromagnetic articulography (EMA) system.

The Effects of a Choral Singing Intervention on Speech Characteristics in Individuals With Parkinson’s Disease: An Exploratory Study

The purpose of this exploratory study was to examine speech characteristics in individuals with Parkinson’s disease (PD) before and after participation in an 11-week choral singing intervention. Speech characteristics were analyzed using an acoustic measure of vowel space area (VSA) and a standardized speech intelligibility metric. Participants included five males and five females with PD. VSA was derived for the corner vowels (/i/, /u/, /æ/ /α/) produced during a sentence-level task. VSA was expressed as an irregular quadrilateral formed by the first and second formants of these corner vowels. A validated speech intelligibility instrument was administered pre- and posttreatment. VSA significantly increased posttreatment, which suggests greater tongue excursion during vowel articulation. Speech intelligibility scores significantly increased posttreatment, thus reflecting improved speech communication. Results suggest that choral singing may be a viable speech treatment for some individuals with PD. A large-scale randomized controlled trial is warranted.

비주얼파닉스를 활용한 조음중재가 청각장애아동의 말 명료도와 모음공간에 미치는 영향*

The purpose of this study was to investigate the effect of articulatory intervention using visual phonics to improve the speech intelligibility of children with impaired hearing. The subjects of the study were five hearing impaired children. As per the results of the UTAP articulation tests, five phonemes with the most frequent errors were selected for each child and a total of 10 sessions were provided. The methodology involved analyzing vowel space and related measures (vowel space area, vowel articulatory index, formant centralization ratio, and F2i/F2u ratio) before and after the visual phonics intervention. After the articulation intervention, every child

Children's Acoustic and Linguistic Adaptations to Peers With Hearing Impairment.

This study aims to examine the clear speaking strategies used by older children when interacting with a peer with hearing loss, focusing on both acoustic and linguistic adaptations in speech. The Grid task, a problem-solving task developed to elicit spontaneous interactive speech, was used to obtain a range of global acoustic and linguistic measures. Eighteen 9- to 14-year-old children with normal hearing (NH) performed the task in pairs, once with a friend with NH and once with a friend with a hearing impairment (HI). In HI-directed speech, children increased their fundamental frequency range and midfrequency intensity, decreased the number of words per phrase, and expanded their vowel space area by increasing F1 and F2 range, relative to NH-directed speech. However, participants did not appear to make changes to their articulation rate, the lexical frequency of content words, or lexical diversity when talking to their friend with HI compared with their friend with NH. Older children show evidence of listener-oriented adaptations to their speech production; although their speech production systems are still developing, they are able to make speech adaptations to benefit the needs of a peer with HI, even without being given a specific instruction to do so. https://doi.org/10.23641/asha.6118817.

Examining Acoustic and Kinematic Measures of Articulatory Working Space: Effects of Speech Intensity.

The purpose of this study was to examine the effect of speech intensity on acoustic and kinematic vowel space measures and conduct a preliminary examination of the relationship between kinematic and acoustic vowel space metrics calculated from continuously sampled lingual marker and formant traces. Young adult speakers produced 3 repetitions of 2 different sentences at 3 different loudness levels. Lingual kinematic and acoustic signals were collected and analyzed. Acoustic and kinematic variants of several vowel space metrics were calculated from the formant frequencies and the position of 2 lingual markers. Traditional metrics included triangular vowel space area and the vowel articulation index. Acoustic and kinematic variants of sentence-level metrics based on the articulatory-acoustic vowel space and the vowel space hull area were also calculated. Both acoustic and kinematic variants of the sentence-level metrics significantly increased with an increase in loudness, whereas no statistically significant differences in traditional vowel-point metrics were observed for either the kinematic or acoustic variants across the 3 loudness conditions. In addition, moderate-to-strong relationships between the acoustic and kinematic variants of the sentence-level vowel space metrics were observed for the majority of participants. These data suggest that both kinematic and acoustic vowel space metrics that reflect the dynamic contributions of both consonant and vowel segments are sensitive to within-speaker changes in articulation associated with manipulations of speech intensity.

Detection of hypernasality based on vowel space area

This study proposes a method for differentiating hypernasal-speech from normal speech using the vowel space area (VSA). Hypernasality introduces extra formant and anti-formant pairs in vowel spectrum, which results in shifting of formants. This shifting affects the size of the VSA. The results show that VSA is reduced in hypernasal-speech compared to normal speech. The VSA feature plus Mel-frequency cepstral coefficient feature for support vector machine based hypernasality detection leads to an accuracy of 86.89% for sustained vowels and 89.47%, 90.57%, and 91.70% for vowels in contexts of high pressure consonants /k/, /p/, and /t/, respectively.

Vowel Space Area of Minangkabau Learners of English

Vowel spacearea (VSA) represents kinematic movements of the articulators and measures speech intelligibility. By looking at the vowel space area, the current study intends to examine the role of Minangkabau in the acquisition of English as a second language. We conducted a speech production experiment involving ten English monophthongs in isolated sentences. We measured the formant frequencies (F1/F2) values and computed the vowel quadrilateral. The results showed that the Minangkabau learners of English did not have similar VSA pattern when compared to the native English speakers. They did not open the jaws and move the tongues as similar as the native English speakers in pronouncing English vowels. The results were discussed in the area of second language acquisition.

A Study on Vowel Space Area and Speech Intelligibility in Children With Articulation Disorder

A Study on Vowel Space Area and Speech Intelligibility in Children With Articulation Disorder

ACOUSTIC MEASUREMENT ON VOWEL PRODUCTION OF ENGLISH AS A SECOND LANGUAGE BY INDONESIAN EFL LEARNERS

Indonesian is the most widely spoken language in Indonesia. More than 200 million people speak the language as a first language. However, acoustic study on Indonesian learners of English (ILE) production remains untouched. The purpose of this measurement is to examine the influence of first language (L1) on English vowels production as a second language (L2). Based on perceptual magnet hypothesis (PMH), ILE were predicted to produce close sounds to L1 English where the vowels are similar to Indonesian vowels. Acoustic analysis was conducted to measure the formant frequencies. This study involved five males of Indonesian speakers aged between 20-25 years old. The data of British English native speakers were taken from previous study by Hawkins & Midgley (2005). The result illustrates that the first formant frequencies (F1) which correlates to the vowel hight of Indonesian Learners of English were significantly different from the corresponding frequencies of British English vowels. Surprisingly, the significant differences in second formant (F2) of ILE were only in the production of /ɑ, ɒ, ɔ/ in which /ɑ/=p 0.002, /ɒ/ =p 0,001, /ɔ/ =p 0,03. The vowel space area of ILE was slightly less spacious than the native speakers. This study is expected to shed light in English language teaching particularly as a foreign language.Keywords: VSA, EFL, Indonesian learners, formant frequencies, acoustic

Acoustic and kinematic analyses of Mandarin vowels in speakers with hearing impairment

ABSTRACTThe central aim of this experiment was to compare acoustic parameters, formant frequencies and vowel space area (VSA), in adolescents with hearing-impaired (HI) and their normal-hearing (NH) peers; for kinematic parameters, the movements of vocal organs, especially the lips, jaw and tongue, during vowel production were analysed. The participants were 12 adolescents with different degrees of hearing impairment. The control group consisted of 12 age-matched NH adolescents. All participants were native Chinese speakers who were asked to produce the Mandarin vowels /a/, /i/ and /u/, with subsequent acoustic and kinematic analysis. There was significant difference between the two groups. Additionally, the HI group produced more exaggerated mouth and less tongue movements in all vowels, compared to their NH peers. Results were discussed regarding possible relationship between acoustic data, articulatory movements and degree of hearing loss to provide an integrative assessment of acoustic and kinematic characteristics of individuals with hearing loss.

Acoustics of Clear and Noise-Adapted Speech in Children, Young, and Older Adults

This study investigated acoustic-phonetic modifications produced in noise-adapted speech (NAS) and clear speech (CS) by children, young adults, and older adults. Ten children (11-13 years of age), 10 young adults (18-29 years of age), and 10 older adults (60-84 years of age) read sentences in conversational and clear speaking style in quiet and in noise. A number of acoustic measurements were obtained. NAS and CS were characterized by a decrease in speaking rate and an increase in 1-3 kHz energy, sound pressure level (SPL), vowel space area (VSA), and harmonics-to-noise ratio. NAS increased fundamental frequency (F0) mean and decreased jitter and shimmer. CS increased frequency and duration of pauses. Older adults produced the slowest speaking rate, longest pauses, and smallest increase in F0 mean, 1-3 kHz energy, and SPL when speaking clearly. They produced the smallest increases in VSA in NAS and CS. Children slowed down less, increased the VSA least, increased harmonics-to-noise ratio, and decreased jitter and shimmer most in CS. Children increased mean F0 and F1 most in noise. Findings have implications for a model of speech production in healthy speakers as well as the potential to aid in clinical decision making for individuals with speech disorders, particularly dysarthria.

Range and Precision of Formant Movement in Pediatric Dysarthria

This study aimed to improve understanding of speech characteristics associated with dysarthria in children with cerebral palsy by analyzing segmental and global formant measures in single-word and sentence contexts. Ten 5-year-old children with cerebral palsy and dysarthria and 10 age-matched, typically developing children participated in this study. Vowel space area and second formant interquartile range were measured from children's elicited productions of single words and sentences. Results showed that the children with dysarthria had significantly smaller vowel space areas than typically developing children in both word and sentence contexts; however, overall ranges of second formant movement did not differ between groups in word or sentence contexts. Additional analysis of single words revealed that, compared to typical children, children with dysarthria had smaller second formant interquartile ranges in single words with phonetic contexts requiring large changes in vocal tract configuration, but not in single words with monophthongs. Results of this study suggest that children with dysarthria may not have globally reduced ranges of articulatory movement compared to typically developing peers; however, they do exhibit reduced precision in producing phonetic targets.

Vowel production of Mandarin-speaking hearing aid users with different types of hearing loss.

In contrast with previous research focusing on cochlear implants, this study examined the speech performance of hearing aid users with conductive (n = 11), mixed (n = 10), and sensorineural hearing loss (n = 7) and compared it with the speech of hearing control. Speech intelligibility was evaluated by computing the vowel space area defined by the Mandarin Chinese corner vowels /a, u, i/. The acoustic differences between the vowels were assessed using the Euclidean distance. The results revealed that both the conductive and mixed hearing loss groups exhibited a reduced vowel working space, but no significant difference was found between the sensorineural hearing loss and normal hearing groups. An analysis using the Euclidean distance further showed that the compression of vowel space area in conductive hearing loss can be attributed to the substantial lowering of the second formant of /i/. The differences in vowel production between groups are discussed in terms of the occlusion effect and the signal transmission media of various hearing devices.

Assessing vowel space area metrics in the context of dialect variation

There has been a growing interest in the development of a sensitive methodology to define a working vowel space area (VSA) as a metric in basic and clinical research applications. In this study, three approaches to the assessment of VSA were tested to evaluate their efficacy in characterizing cross-dialectal and cross-generational variation: The traditional vowel quadrilateral, the traditional convex hull, and a more liberal convex hull. In the two traditional approaches, VSA was computed as a planar convex polygon shaped by phonologically distinct vowel categories as its corners. The mean F1/F2 values at vowel midpoint were used to define the respective areas. The liberal convex hull utilized vowel dynamics and variable F1/F2 temporal locations to refine the outer boundaries and maximize the VSA. This approach used an unrestricted number of vowels and measurement locations to define the optimal VSA. All computations were based on a common speech material produced by 135 female speakers representing three American English dialects and four generations ranging from 8 to 91-year olds. The three metrics yielded inconsistent and contradictory estimates of VSA. Discussion will focus on the limited utility of polygon geometry in characterizing a working VSA in American English dialects.

Relation between acoustic-phonetic properties and speech intelligibility in noise obtained with bilingual talkers

An objective, language-independent way of predicting observed differences in speech intelligibility in noise across talkers based on their acoustic-phonetic properties was pursued by exploiting speech intelligibility data in stationary speech-shaped noise uttered by bilingual talkers and comparing inter-individual as well as intra-individual speech feature variations across languages. Matrix sentence materials were used that were uttered by bilingual talkers of German/Spanish and of German/Russian and by the respective original matrix test talkers. Various acoustic-phonetic parameters discussed in the literature as being related to speech intelligibility were determined for each talker. Vowel space area, between-vowel category dispersion, and energy in the mid-frequency region represented by the speech intelligibility index were found to be language-independent acoustic-phonetic properties most strongly related to speech intelligibility at least for German, Russian and Spanish. Generally larger inter-individual variation within languages than intra-individual variation across languages was found. Hence, objective phonetic criteria like vowel space area may be used in the future to objectively assess the potential of a talker to be easily understood in a noisy background. One reason of the generally poorer intelligibility performance of Spanish compared to German or Russian may lie in the usage of considerably smaller vowel space areas.

Predicting intelligibility of dysphonic speech with automatic measurement of vowel related parameters

Speakers with dysphonia frequently report difficulty with being understood in noisy places. Perception of vowels plays an important role in intelligibility. Dysphonic speech is typically characterized both by shorter periodic intervals and an increased proportion of noise vs. harmonic components, potentially obscuring acoustic cues for identification of vowels. This study examined whether vowel-related acoustic measures would predict intelligibility of dysphonic speech. Sentences from the Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) were recorded from 18 dysphonic speakers (6 adult females, 6 adult males, and 6 children) and 3 normal speakers (1 adult female, 1 adult male, and 1 child). These sentences were analyzed acoustically by SpeechMark® Wavesurfer plug-in version, a speech analysis tool based on the landmark theory of speech perception. The sentences were presented to 45 listeners for perceptual rating of intelligibility at 3 S/N ratios. The following output parameters were compared: vowel space area, number of vowels whose F1 and F2 values fell within a standard vowel quadrilateral (defined based on existing literature), and number of vowels with normal formant bandwidth. Preliminary results indicated that number of vowels with normal formant bandwidth falling within the quadrilateral significantly predicted the intelligibility ratings of dysphonic speech at all noise levels.

Effect of Treatment on Oral Motor for Children with Spastic Cerebral Palsy

The purpose of the report was to find out the effects of oral motor treatment on the functional practice of the articulator and articulation for children with spastic cerebral palsy in pre-and-post treatment. Two children with spastic cerebral palsy at the age of six in average were practiced with a speech therapist each for 20minutes by 40 times. Vowels /a/, /i/, /u/, /e/, /o/ assessed the percentage of correct vowels and formant and nine syllables, which combined with bilabial plosives /p, p’, p h / and vowels(/a/, /i/, /u/) assessed the percentage of correct consonants and the voice onset time(VOT) of bilabial plosives. These were recorded on Multi-Speech, evaluated auditory-perceptually, and analyzed by acoustic parameters. As a result, the functional practice of the articulator was improved in post-treatment compared with pre-treatment for the subjects. The percentage of correct vowels and consonants were improved in post-treatment compared with pre-treatment. The formant of vowel /i/(F1) and formant of vowels /u, o/(F2) were decreased and the formant of vowel /i/(F2) was increased in pot-treatment for the subjects. The vowel space area(VSA) was larger in post-treatment for the subjects. The VOT of tensed sounds were decreased in post-treatment compared with pre-treatment. As control of lips, tongue, jaw and articulation of vowels and consonants improved through oral motor treatment for children with spastic cerebral palsy, the consistently intervention of treatment and the development of individualized treatment programs according to degree of disability and ability of articulation are needed for children with spastic cerebral palsy.

Divergent acoustic properties of gelada and baboon vocalizations and their implications for the evolution of human speech.

Human speech has many complex spectral and temporal features traditionally thought to be absent in the vocalizations of other primates. Recent explorations of the vocal capabilities of non-human primates are challenging this view. Here, we continue this trend by exploring the spectro-temporal properties of gelada (Theropithecus gelada) vocalizations. First, we made cross-species comparisons of geladas, chacma baboons, and human vowel space area. We found that adult male and female gelada exhaled grunts-a call type shared with baboons-have formant profiles that overlap more with human vowel space than do baboon grunts. These gelada grunts also contained more modulation of fundamental and formant frequencies than did baboon grunts. Second, we compared formant profiles and modulation of exhaled grunts to the derived call types (those not shared with baboons) produced by gelada males. These derived calls contained divergent formant profiles, and a subset of them, notably wobbles and vocalized yawns, were more modulated than grunts. Third, we investigated the rhythmic patterns of wobbles, a call type shown previously to contain cycles that match the 3-8 Hz tempo of speech. We use a larger dataset to show that the wobble rhythm overlaps more with speech rhythm than previously thought. We also found that variation in cycle duration depends on the production modality; specifically, exhaled wobbles were produced at a slower tempo than inhaled wobbles. Moreover, the variability in cycle duration within wobbles aligns with a linguistic property known as 'Menzerath's law' in that there was a negative association between cycle duration and wobble size (i.e. the number of cycles). Taken together, our results add to growing evidence that non-human primates are anatomically capable of producing modulated sounds. Our results also support and expand on current hypotheses of speech evolution, including the 'neural hypothesis' and the 'bimodal speech rhythm hypothesis'.

Phonologic and Acoustic Analysis of Speech Following Glossectomy and the Effect of Rehabilitation on Speech Outcomes

Changes in acoustic features in the perioperative phase for elucidating the mechanisms of articulation disorder and the effect of perioperative rehabilitation were studied prospectively. Sixty-two patients with 62 tongue cancer were divided into a partial glossectomy group (n= 40) and a reconstruction group (n= 22). Acoustic characteristics were analyzed during the preoperative and postoperative periods and after rehabilitation using the first and second formants of the vowels /a/, /i/, and /u/; the triangular vowel space area (tVSA); and the slopes of formant transitions. In the 2 groups, decreases in the tVSA and formant slopes were found from the preoperative to the postoperative period, and the acoustic characteristics of the reconstruction group especially improved to preoperative values after rehabilitation. Analysis of the postoperative period showed that acoustic characteristics were altered at the site of surgical resection. Changes of acoustic variables are related to excision size and site, suggesting the distinctive tongue portion for the articulation of each speech sound. Perioperative rehabilitation could activate the articulators and increase the range of movement of the remaining tongue, especially the preserved anterior tongue.