• 음성과학
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• 제7권4호
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• pp.169-186
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• 2000

This paper aims to confirm the mispronunciation of native Korean students due to the phonetic and phonological system differences between English and Korean, and to find the works-to-do by experiment. Many Korean students tend to differentiate the sounds of word-final stop consonants not by vowel duration or the allophones but by the phoneme of the consonant itself. In English, Stop sounds change through the conditions of the aspirated, unaspirated, or unreleased sounds. But in Korean they are not allophones of phonemes but distinct phonemes. Therefore, many Korean students are apt to add an extra vowel sound /i/ after the final stop consonant in the eve form due to both the unperception of the differences between the phonemes and the allophones of stop consonants, and the influence of the Korean sound-sequence relationship. Since the replacement of the allophones and extra vowel addition does not change the meaning, the importance was almost lost. Nevertheless, this kind of study is essential for the precise learning and the use of the English language.

• 말소리와 음성과학
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• 제9권2호
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• pp.1-7
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• 2017

The purpose of this study is to investigate the relations between phonetic differences among Korean learners' production of English front vowels, pronunciation intelligibility and speaking proficiency test score. To do so, thirty Korean university students were asked (1) to read English text book paragraphs and (2) describe a picture. Two English native raters and one Korean rater evaluated Korean subjects' English pronunciation intelligibility and speaking. In addition, subjects' English vowel productions were acoustically analyzed(F0, F1, F2, vowel duration, intensity). The results of the study show that the vowel quality and pitch of the unstressed vowels and lax vowel are related to the pronunciation intelligibility. In addition, the scores of pronunciation intelligibility and speaking are highly related.

• 말소리와 음성과학
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• 제8권3호
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• pp.11-20
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• 2016

It is well known that vowels are shorter before voiceless consonants than voiced ones in English, as in many other languages. Research has shown that the ratio of vowel durations in voiced and voiceless contexts in English is in the range of 0.6~0.8. However, little work has been done as to whether the ratio of vowel durations varies depending on English variety. In the production experiment in this paper, seven speakers from three varieties of English, New Zealand, British, and American English, read 30 pairs of (C)VC monosyllabic words which differ in coda voicing (e.g. beat-bead). Vowel height, phonemic vowel length, and consonant manner were varied as well. As expected, vowel-shortening effects were found in all varieties: vowels were shorter before voiceless than before voiced codas. Overall vowel duration was the longest in American English and the shortest in New Zealand (NZ) English. In particular, vowel duration before voiceless codas is the shortest in New Zealand English, indicating the most radical degree of shortening in this variety. As a result, the ratio of vowel durations in varying voicing contexts is the lowest in NZ English, while American and British English do not show a significant difference each other. In addition, consonant closure duration was examined. Whereas NZ speakers show the shortest vowel duration before a voiceless coda, their voiceless consonants have the longest closure duration, which suggest an inverse relationship between vowel duration and closure duration.

• 음성과학
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• 제13권1호
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• pp.7-27
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• 2006

This study explored the discrimination of synthesized English vowel pairs by twenty-seven American and Korean, male and female listeners. The average formant values of nine monophthongs produced by ten American English male speakers were employed to synthesize the vowels. Then, subjects were instructed explicitly to respond to AX discrimination tasks in which the standard vowel was followed by another one with the increment or decrement of the original formant values. The highest and lowest formant values of the same vowel quality were collected and compared to examine patterns of vowel discrimination. Results showed that the American and Korean groups discriminated the vowel pairs almost identically and their center formant frequency values of the high and low boundary fell almost exactly on those of the standards. In addition, the acceptable range of the same vowel quality was similar among the language and gender groups. The acceptable thresholds of each vowel formed oval to maintain perceptual contrast from adjacent vowels. The results suggested that nonnative speakers with high English proficiency could match native speakers' performance in discriminating vowel pairs with a shorter inter-stimulus interval. Pedagogical implications of those findings are discussed.

• 말소리와 음성과학
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• 제7권1호
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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.

• 말소리와 음성과학
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• 제4권2호
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• pp.61-70
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• 2012

The current study observes the durational interaction of tautosyllabic consonants and vowels in the word-initial position of English and Korean child-directed speech (CDS). The effect of phonological laryngeal contrasts in stops on the following vowel duration, and the effect of the intrinsic vowel duration on the release duration of preceding stops in addition to the acoustic realization of the contrastive segments are explored in different prosodic contexts - phrase-initial/medial, focal accented/non-focused - in a marked speech style of CDS. A trade-off relationship between Voice Onset Time (VOT), as consonant release duration, and voicing phonation time, as vowel duration, reported from adult-to-adult speech, and patterns of durational variability are investigated in CDS of two languages with different linguistic rhythms, under systematically controlled prosodic contexts. Speech data were collected from four native English mothers and four native Korean mothers who were talking to their one-word staged infants. In addition to the acoustic measurements, the transformed delta measure is employed as a variability index of individual tokens. Results confirm the durational correlation between prevocalic consonants and following vowels. The interaction is revealed in a compensatory pattern such as longer VOTs followed by shorter vowel durations in both languages. An asymmetry is found in CV interaction in that the effect of consonant on vowel duration is greater than the VOT differences induced by the vowel. Prosodic effects are found such that the acoustic difference is enhanced between the contrastive segments under focal accent, supporting the paradigmatic strengthening effect. Positional variation, however, does not show any systematic effects on the variations of the measured acoustic quantities. Overall vowel duration and syllable duration are longer in English tokens but involve less variability across the prosodic variations. The constancy of syllable duration, therefore, is not found to be more strongly sustained in Korean CDS. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• 말소리와 음성과학
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• 제8권3호
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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.

• 말소리와 음성과학
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• 제6권2호
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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.

• 말소리와 음성과학
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• 제5권2호
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• pp.53-58
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• 2013

The purpose of this study is to compare the first two vowel formants of the stressed and unstressed English vowels produced by ten young males (in their twenties and thirties) and ten old males (in their forties or fifties) from the Buckeye Corpus of Conversational Speech. The results indicate that the stressed and unstressed vowels, /i/ and $/{\ae}/$ in particular, from the two groups are different in their formant frequencies. In addition, the vowel space of the unstressed vowels is somewhat smaller than that of the stressed vowels. Specifically, the range of the second formant of the unstressed vowels and that of the first formant of the unstressed front vowels were compressed. The findings from this study can be applied to the pronunciation training for the Korean learners of English vowels. We propose that teachers of English pay attention to the stress patterns of English vowels as well as their formant frequencies.

• 대한의용생체공학회:의공학회지
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• 제9권1호
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• pp.1-10
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• 1988

In this study, the recognition experiments for Korean vowel are performed using peripheral auditory model. In addition, for the purpose of objective comparison, the recognition experiments are performed by extracting LPC cepstrum coefficients for the same speech data. The results are as follows. 1) The time and the frequency responses of the auditory model show that important features of input signal are involved in the responses of inner ear and auditory nerve. 2) The recognition results for Korean vowel show that the recognition rate by auditory model output is higher than the recognition rate by LPC cepstrum coefficients. 3) The adaptation phenomenon of auditory nerve provides useful characteristics for the discrimination of vowel signal.