• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.79-86
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• 2015

This study explored the vowel effect on acoustic perturbation measures in voice quality analysis. For this study, the perturbation parameters (%jitter, %shimmer) and noise parameter (SNR) were measured with 7 Korean vowels (/a/, /ɛ/, /i/, /o/, /u/, /ɯ/, /ʌ/) using CSpeech with 50 Korean normal young adults (24 males and 26 females). A significant vowel effect was found only in %shimmer and in particular, low-back /a/vowel was significantly different from other vowels in %shimmer. The least perturbation and noise were exhibited on high-back /ɯ/ and /o/ vowel, respectively. Based on tongue height, a significant higher %shimmer was demonstrated on low vowels than high vowels. In addition, back vowels in tongue advancement and rounded vowels in lip rounding showed significantly less perturbation and noise. The least variability of perturbation and noise within individuals was demonstrated on the vowel /i/ in three repeated measures. However, there was no significant difference among 3 token measures in single session among vowels tested except the vowel /o/. Consequently, the vowel /a/ commonly used in acoustic perturbation measures exhibited higher perturbation and noise whereas higher stability and less variability were demonstrated on the high-back vowel /u/. These results suggested that the Korean high-back vowel /u/ can be more appropriate and reliable for perturbation acoustic measures.

• Speech Sciences
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• v.10 no.3
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• pp.157-173
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• 2003

The purpose of this experimental study is to investigate and compare the. vowel lengths of English diphthongs and low vowels among native-English-speaking Americans with Korean college students from the Chungnam and Gyungnam provinces. Eight words and sixteen sentences were uttered five times by twenty five subjects from three groups; 1) Chungnam dialect speakers, 2) Gyungnam dialect speakers and 3) five native-English-speaking Americans. Acoustic features (duration) were measured from sound spectrograms made by the PC Quire. Results showed that the vowel lengths of English diphthongs and low vowels between native English speakers and Korean collegians of Chungnam and Gyungnam provinces were different. Comparing the average length of English diphthongs of Korean collegians with those of American natives, we can see that native English speakers tend to pronounce the English diphthongs shorter than Korean collegians do. However, native English speakers tend to pronounce the English low vowels longer than Korean collegians do. In this study we also tried to find out the differences of English diphthongs and low vowel lengths in relation to their utterance positions among American natives and Chungnam and Gyungnam dialect speakers. By the results of this experiment, we observed a lengthening effect in the three groups. However, in the pronunciation of American natives, a lengthening effect of English vowels was more clearly observed, especially in the pronunciation of English diphthongs.

• Phonetics and Speech Sciences
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• v.6 no.4
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• pp.91-99
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• 2014

Speaking styles tend to have an influence on spectral characteristics of produced speech. There are not many studies on the spectral characteristics of speech because of complicated processing of too much spectral data. The purpose of this study was to examine spectral characteristics and formant bandwidths of English vowels produced by nine American males with different speaking styles: clear or conversational styles; high- or low-pitched voices. Praat was used to collect pitch-corrected long-term averaged spectra and bandwidths of the first two formants of eleven vowels in the speaking styles. Results showed that the spectral characteristics of the vowels varied systematically according to the speaking styles. The clear speech showed higher spectral energy of the vowels than that of the conversational speech while the high-pitched voice did the same over the low-pitched voice. In addition, front and back vowel groups showed different spectral characteristics. Secondly, there was no statistically significant difference between B1 and B2 in the speaking styles. B1 was generally lower than B2 when reflecting the source spectrum and radiation effect. However, there was a statistically significant difference in B2 between the front and back vowel groups. The author concluded that spectral characteristics reflect speaking styles systematically while bandwidths measured at a few formant frequency points do not reveal style differences properly. Further studies would be desirable to examine how people would evaluate different sets of synthetic vowels with spectral characteristics or with bandwidths modified.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.119-129
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• 2015

This paper investigates the status of the merger between the mid front unrounded vowels ㅔ[e] and ㅐ[${\varepsilon}$] in contemporary Korean. Our analysis is based on a balanced corpus of production and perception data from young subjects from three dialectal areas (Seoul, Daegu and Gwangju). Except for expected gender differences, the production data display no difference in the realization of these vowels, in any of the dialects. The perception data, while mostly in line with the production results, show that Seoul females tend to better discriminate the two vowels in terms of perceived height: vowels with a lower F1 are more likely to be categorized as ㅔ by this group. We then investigate the possible causes of this merger: based on an empirical study of transcribed spoken Korean, we show that the pair of vowels ㅔ/ㅐ has a very low functional load. We argue that this factor, together with the phonetic similarity of the two vowels, may have been responsible for the observed merger.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.1
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• pp.45-51
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• 2002

The purpose of this study is to examine the effects of vowel type on the nasalance score. Twenty one male adults without VPI produced 5 types of vowels (/a/, /e/, /i/, /o/, /u/) in two conditions-normal and simulated VPI condition. Nasalance scores were measured for each vowel. These data were compared between conditions and among vowel types. The results were as follow : For all vowels, nasalance scores were significantly higher in simulated VPI condition than in normal condition. The two conditions yielded different patterns in terms of the degree of nasalance across the 5 vowels. In normal condition, nasalance scores were higher in front vowels than in medial or back vowels. But in simulated VPI condition, nasalance scores were higher in high vowels than in mid or low vowels.

• Speech Sciences
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• v.12 no.2
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• pp.7-16
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• 2005

The purpose, this experimental study was to identify pronunciation difficulties between male and female Korean speakers in their articulation of English vowels. Ten English mono-syllabic words were spoken six times by six male and six female college students. Formant frequencies were measured from sound spectrograms made by Pitch Works. Results show that Korean female speakers uttered English vowels more similar to those uttered by English native speakers than did Korean male speakers. While Korean male speakers could not readily distinguish between /i/ and /I/, /u/ and /v/, and /$\epsilon$/ and /ae/, respectively, Korean female speakers had difficulty only with /$\epsilon$/ and /ae/. The tentative results suggests that on the whole Korean speakers have difficulty in discriminating tense vowels from lax vowels, and they also have articulatory problems pronouncing low and back vowels such as /ae/. /a/ and /c/.

• Speech Sciences
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• v.9 no.4
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• pp.175-185
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• 2002

The purpose of this study was to investigate the acoustic durations of Korean vowels followed by either voiced or voiceless consonants. Six healthy adult speakers (2 females and 4 males) recorded nonsense syllables in which voiced (/b, d, g/) or voiceless (/p', t', k', $p^{h},t^{h},k^{h}$) consonants follow three different vowels (/i, a, u/) embedded in a carrier phrase. Results showed that vowels preceding voiced consonants (e.g., haba) were significantly longer in duration than those preceding voiceless consonants (e.g., hiP' a or $hip^{h}a$). Also vowels were longer in duration when occurring before velar-stops than before bilabial-stop and dental-stops. Finally, the duration of the low vowel (/a/) was substantially longer than that of the high vowels (/i, u/). These findings may be applicable to speech synthesis or therapy.

• Speech Sciences
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• v.7 no.3
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• pp.99-108
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• 2000

The purpose of this experimental study was to investigate characteristics of English vowels as spoken by Korean speakers. Ten English mono-syllabic words were spoken six times by six male college students who were born and raised in Seoul. Formant frequencies were measured from sound spectrograms made by the PC Quirer. Results showed that Korean speakers similarly pronounced /i/ and /I/, /u/ and /$\upsilon$/, and /$\varepsilon$/ and /${\ae}$/ respectively. It seems that Korean speakers can not differentiate tense vowels(/i/, /u/) from lax vowels(/i/, /$\upsilon$/) and pronounce low vowels such as /${\ae}$/, /a/, /c/ clearly. It is necessary that Korean speakers practice the correct movements of the jaw, tongue, and lips when they pronounce English vowels.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.99-107
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• 2013

The purpose of this study is to examine the relative distances among English front vowels in a message produced by 47 Korean and American speakers in order to better instruct pronunciation skills of English vowels for Korean English learners. A Praat script was developed to collect the first and second formant values(F1 and F2) of eight words in each sound file which was recorded from an internet speech archive. Then, the Euclidean distances were measured between the three vowel pairs: [i-ɛ], [i-ɪ], and [ɛ-æ]. The first vowel pair [i-ɛ] was set as the reference from which the relative distances of the other two vowel pairs were measured in percent in order to compare the vowel sounds among speakers of different vocal tract lengths. Results show that F1 values of the front vowels produced by the Korean and American speakers increased from the high front vowel to the low front vowel wih differences among the groups. The Korean speakers generally produced the front vowels with smaller jaw openings than the American speakers did. Secondly, the relative distance of the high front vowel pair [i-ɪ] showed a significant difference between the Korean and American speakers while that of the low front vowel pair [ɛ-æ] showed a non-significant difference. Finally, the Korean speakers in the higher proficiency level produced front vowels with higher F1 values than those in the lower proficiency level. The author concluded that Korean speakers should produce the front high vowels distinctively by securing sufficient relative distance of the formant values. Further studies would be desirable to examine how strong the Korean speakers' English proficiency correlate with the relative distance of target words of comparable productions.

• Korean Journal of Cognitive Science
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• v.15 no.1
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• pp.1-11
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• 2004

The aim of this study is to reveal the order and the age of mastery of phonemic contrast in vowel sounds of Korean. For this purpose, we made an observation of the correspondences between the sounds produced by children of 12-35 months and the target sounds produced by adults. The provisional order and the age of contrast acquisition shown from the results of this study are as follows. First, the differential production of vowels by the feature relating to the body of the tongue precedes the differential production of vowels by the feature relating to the lip rounding. Second, as for the differential production of vowels by the feature relating to the body of the tongue, the contrast between the low vowels and the others is accomplished first, and the contrast between the high and low vowels and the contrast between the front and the back vowels are established around the age of 24 months. Third, as for the differential production of vowels by the feature relating to the lip rounding, the contrast between the rounded and the unrounded vowel is not accomplished until 36 months. Finally, we observed, prior to the completion of the differential production of phonemes, children use a specific phoneme excessively. This passing phrase could be interpreted as a result of over-application of a distinctive feature in the course of acquisition of it.