• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.185-192
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• 2010

The acoustic vowel space has been used as an acoustic parameter in dysarthric speech. The aim of this work was to examine mathematical formulae for acoustic vowel space and to apply these to Korean speakers with idiopathic Parkinson's disease(IPD). Five acoustic parameters were chosen from earlier works and one new parameter was proposed, the pentagonal vowel space. The six parameters included triangular vowel space (3 area), irregular quadrilateral vowel space (4 area), irregular pentagonal vowel space (5 area), vowel articulatory index (VAI), formant centralization ratio (FCR) and F2i/F1u ratio (F2 ratio). An experimental group of 32 IPD patients(male:female=16:16) and a control group of twenty healthy people (male:female=8:12) participated in the study and repeated vowels (/a-i-u-e-o/) three times. A correlation analysis was performed among the six parameters, 2-way ANOVA was done with gender and groups as independent factors, and an independent sample t-test was conducted between the male and the female group as post hoc comparison. All parameters were highly correlated with each other and only the FCR showed a high negative correlation with the others. The results of ANOVA showed a significant difference in F2 ratio, 3 area, 4 area and 5 area between gender and in 4 area and 5 area between groups. For the male members of the two groups, significant statistical differences were found in all parameters whereas no such differences were found for the female members. These findings indicated that the vowel space of the female group was wider than the vowel space of the male group. These differences may have been caused by gender-specific speech styles rather than by patho-physiological mechanisms. We also claim that the pentagonal vowel space is better than the other vowel spaces at representing the disordered speech in natural speech situations.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.89-96
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• 2014

This study measured speech intelligibility in relation to the vowel space area and the perception of the listener through acoustic analysis of children who had received cochlear implants. It also provided basic data in the evaluation of speech intelligibility by analyzing the correlation between the vowel space area and speech intelligibility. As a research method, the vowel space area was analyzed by obtaining the value of $F_1$, $F_2$ in children three years after receiving cochlear implants, and compared them to normal children by measuring speech intelligibility through interval scaling. A product-moment correlation analysis was conducted to investigate the correlation. Results showed that the vowel space area of the children who had received cochlear implants was significantly different from that of the normal children, though their speech intelligibility showed similar points to those of the normal children. The results of the correlation analysis on the vowel space area and speech intelligibility showed no significant correlation. Therefore, the period of improving intelligibility after receiving cochlear implants and the objective standards of the vowel space area could be established. In addition, the acoustic rating was required to increase the accuracy of the objective measurement in the evaluation of speech intelligibility.

• Phonetics and Speech Sciences
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• v.2 no.2
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• pp.85-92
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• 2010

The purpose of this study was to know the differences in perceptual judgement for speech intelligibility in monosyllables by inexperienced listeners and vowel space area according to different dysarthric severity. Three dysarthric speakers with different severity(mild, moderate and severe) screened by 3 clinicians' screening tests before the experiment were conducted. Corner vowels (i, u, ae, a) in monosyllable level (CVC, 'p_p') and carrier phrases ('종이에_써') were chosen and analyzed for vowel space. Inexperience listeners (n=20) performed the intelligibility test for spoken syllables and carrier phrases by dysarthric speakers. The results show that there is a significant differences in both F1 and F2 values among 4 corner vowels. Vowel space area in the data of mildly impaired speakers was significantly higher than two others. In the scores of speech intelligibility judged by inexperienced listeners, the scores by a moderately impaired speaker were more higher than two other speakers. The discrepancy between perceptual judgement by inexperienced listeners and vowel space area will be discussed in this area.

• Phonetics and Speech Sciences
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• v.10 no.2
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• pp.85-96
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• 2018

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's speech intelligibility improved, their vowel space area was widened, the FCR value decreased, and the F2ratio value increased. These results show that the use of visual phonics through symbolic images and hand clues has a positive effect in terms of improving the speech intelligibility of children with impaired hearing.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.161-169
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• 2012

The purpose of this study was to investigate the characteristics of speech intelligibility of spontaneous speech and the vowel space parameters in patients with Parkinson's disease. Ten PD patients (M=5, F=5) and a corresponding control group of ten normal adults participated in this study. Firstly, subjects were asked to tell a story about their hometown and youth in order to analyze speech intelligibility. Secondly, the subjects were also asked to repeat four vowels (/a/, /i/, /u/, /e/) five times in order to compare their vowel spaces. The results were as follows: (1) the speech intelligibility of the PD group was lower than that of the control group. (2) Four parameters including vowel area, vowel articulatory index, formant centralization ratio, F2i/F1u ratio were significantly different in each group. For instance, vowel area and F2 ratio were wider and higher, respectively. As a result, a decrease in speech intelligibility of patients with PD is likely to show different types of errors from the normal group. The results of this research are meaningful in a sense that they could provide the objective standard of speech intelligibility and vowel space parameters.

• Speech Sciences
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• v.1
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• pp.201-211
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• 1997

Acoustically a naturally-spoken vowel is composed of five formants. However, the acoustic quality of a vowel is known to be mostly determined by $F_1\;and\;F_2$. The main purpose of this study was to examine how synthesized vowels with $F_1\;and\;F_2$ are perceived by Korean native speakers. In addion, we are interested in finding whether the synthesized vowels are perceived differently by standard Korean speakers and Kyungnam regional dialect speakers. In the experiment 9 Seoul standard Korean speakers and 9 Kyungnam dialect speakers heard 536 vowels synthesized in vowel space with $F_1\;by\;F_2$ and categorized them into one of 10 Korean vowels. The resultant vowel map showed that each Korean vowel occupies an unique area in the two-dimensional vowel space of $F_1\;by\;F_2$, and confirmed that $F_1\;and\;F_2$ play important roles in the perception of vowels. The results also showed that the Seoul speakers and the Kyungnam speakers perceive the synthesized vowels differently. For example, /e/ versus /$\varepsilon$/ contrast, /y/, and /$\phi$/ are perceived differently by the Seoul speakers, whereas they were perceptually confused by the Kyungnam speakers. These results might be due to the different vowel systems of the standard Korean and the Kyungnam regional dialect. While the latter uses a six-vowel system which has no /e/ vs /$/ contrast, /v/ vs /i/ contrast, /y/, and /$\phi$/, the former recognizes these as different vowels. This result suggests that the vowel system of differing dialect restricts the perception of the Korean vowels. Unexpectedly /i/ does not occupy any area in the vowel apace. This result suggests that /i/ cannot be synthesized without $F_3$.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.229-238
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• 2010

This study investigates the differences in acoustic parameters in vowel space across hearing loss, gender and vowels. The parameters include F1, F2, Euclidean Distance between vowels, and vowel triangular area comprised of /i/, /a/ and /u/. For this study, 20 hearing-impaired and normal hearing adults as a control group were asked to read 7 Korean vowels (/a, $\wedge$, o, u, w, i, $\varepsilon$/). Subjects' readings were recorded by NasalView and analyzed by Praat. Results showed that F1 were significantly higher in the hearing impaired group than in the normal hearing group, higher in the female group than in male group, and higher in low vowels than in high vowels. And the means of F2 was significantly higher in the hearing impaired group than in normal hearing group, higher in high vowels than in low vowels, and there was no difference between male and female group. Secondly, Euclidean distance between vowels was significantly shorter in the hearing-impaired group than in the normal group. Finally, acoustic vowel space area was significantly smaller in the hearing-impaired group than in the normal hearing group. The hearing-impaired group showed that front vowels tended to be backed and back vowels to be fronted.

• Phonetics and Speech Sciences
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• v.8 no.3
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• pp.51-59
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• 2016

The purpose of present study is to examine differences between habitual speech (HS) and clear speech (CS) in individuals with mild dysarthria. Twelve speakers with mild dysarthria and twelve healthy control speakers read sentences in two speaking styles. Formant and intensity related values, triangular area, and center of gravity of /a/, /i/, and /u/ were measured. In addition, formant-ratio variables such as vowel space area(VSA), vowel articulatory index (VAI), formant centralization ratio (FCR) and F2i/F1u ratio (F2 ratio) were calculated. The results of repeated-measures ANOVA showed a significant difference in F2 of vowel /i/ and F2 energy of vowel /a/ between groups. Regarding formant energy, F2 energy of vowel /a/ were observed as meaningful variables between speaking styles. There were significant speaking style-by-group interactions for F2 energy of vowel /a/. These findings indicated that current parameters could discriminate healthy group and mild dysarthria group meaningfully and that speaker with dysarthria had larger clear speech benefit than healthy talkers. We also claim that various acoustic changes of clear speech may contribute to improving vowel intelligibility.

• The Journal of Advanced Prosthodontics
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• v.2 no.3
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• pp.71-76
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• 2010

PURPOSE. The purpose of this study was to compare men with women in terms of speech intelligibility, to investigate the validity of objective acoustic parameters related with speech intelligibility, and to try to set up the standard data for the future study in various field in prosthodontics. MATERIALS AND METHODS. Twenty men and women were served as subjects in the present study. After recording of sample sounds, speech intelligibility tests by three speech pathologists and acoustic analyses were performed. Comparison of the speech intelligibility test scores and acoustic parameters such as fundamental frequency, fundamental frequency range, formant frequency, formant ranges, vowel working space area, and vowel dispersion were done between men and women. In addition, the correlations between the speech intelligibility values and acoustic variables were analyzed. RESULTS. Women showed significantly higher speech intelligibility scores than men and there were significant difference between men and women in most of acoustic parameters used in the present study. However, the correlations between the speech intelligibility scores and acoustic parameters were low. CONCLUSION. Speech intelligibility test and acoustic parameters used in the present study were effective in differentiating male voice from female voice and their values might be used in the future studies related patients involved with maxillofacial prosthodontics. However, further studies are needed on the correlation between speech intelligibility tests and objective acoustic parameters.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.75-83
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• 2017

The purpose of this study is to find clues to the risk of voice disorders in soprano students. The subjects of the study were 17 soprano students and 18 general students (women). The phonation of vowels /a/, /i/, and /u/ with C4 and F4 notes in each group were recorded. Then, only soprano students were made to record their classical vocalization containing vibrato. Formant, formant energy, bandwidth, VAI (vowel area index), VSA (vowel space area) and L/H ratio were analyzed. There was significant difference in F3 such that the singers' note was measured around 3 kHz which seems to be 400 Hz higher than one from general students. But, There was no significant difference in L/H ratio between soprano student and the general student. There was a significant difference in F3 in the comparison of the soprano students' two vocalization methods. Classical vocalization was measured at 200Hz higher than sustained phonation in F3. Vocal tract adjustment was made and vowel space changed, but there was no significant difference in F3 energy, which is the index of singers' formant according to the phonation method. The L/H ratio, which can be a direct indicator of vocal effort, has no difference in phonation method and is lowered in all phonation methods as the pitch increases. C4 and F4 pitches are lower than the singing range of the soprano. When the pitch changes, vocal effort increases like a general student which will be an indicator of the risk of vocalization. This will be a clue to the vocalization of the immature soprano student.