• 인터넷정보학회논문지
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• 제6권6호
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• pp.179-186
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• 2005

음성학에서 음성이 가지고 있는 주파수 특성을 이용하여 스펙트럼을 추출할 수 있고 이를 이용하여 음성을 분석할 수 있다. 그러나 음성의 스펙트럼은 단모음의 경우 어느 정도 일정한 형태를 유지하지만 음절. 단어 등과 같이 자음과 모음이 서로 결합되었을 때는 상당한 변화가 발생된다. 이는 음소단위 음성인식에 있어서 가장 큰 장애가 되고 있다. 본 논문에서는 주파수 영역과 청각적 인상을 고려한 멜 대역 그리고 멜 켑스트럼을 이용하여 각 자음과 모음이 가지고 있는 스펙트럼을 분석하고, 청각적 특성을 반영한 음성의 변화를 체계화하여 음성을 음소단위로 분할할 수 있는 기반을 제공한다.

• 대한치과교정학회지
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• 제21권2호
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• pp.287-307
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• 1991

This study aimed at examining speech defects of openbite patients, which were analized in terms of formant frequency for vowels and word pronunciation length for consonants. In addition, the upper and lower lip (perioral m.) activity was tested by the EMG. The tongue force was measured by the strain gauge, and the speech discrimination test was carried out. One experimental group and one control group were used for this study and they were respectively composed of six female openbite patients and six normal-occlusion females. Eight monophthongs, two fricatives and two affricatives were chosen for speech analysis. Speeches of the above-mentioned groups were recorded and then analized by the ILS/PC-1 software. Four hundred most frequently used monosyllables were also chosen for discrimination score. Openbite patients showed the following characteristics: 1. Abnormality in case of /a/, $/\varepsilon/$, /e/, /i/ $F_2$ and /e/, /a/ $F_1$. 2. Significantly elongated length in their pronunciation of /h/ and $/C^h/$ and somewhat elongated length also in their pronunciation of /s/ and /c/. 3. Significant upper lip activity according to the EMG test during pronunciation of the bilabial consonants. 4. Relatively weak tongue force according to the strain gauge measurement. 5. According to the speech discrimination test, high rate of misarticulation in case of (a) initial /p/ /s'/ and /ts'/, (b) /a/,$/\varepsilon/$,/e/,/je/,/o/, $/\phi/$,/jo/,/u/,/we/, and /i/ (c) final (equation omitted).

• 대한음성학회지:말소리
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• 제39호
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• pp.73-86
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• 2000

This paper aims to research the influence of mother tongue (Polish) on the perception of a foreign language (Korean) i.e. how vowel sounds that are totally unfamiliar to the listeners are perceived, how the similar sounds are perceived and whether the perception differs according to the phonetic values of the neighbouring sounds. As a result, the degree of the influence of Ll on the vowels of L2 is different in each case and mostly depends on the familiarity of the vowel in question and on the articulatory similarities between the vowels in both languages. The results are as follows; The best perception was observed with Korean /i/ and /a/ (very similar places of articulation in both languages). The worst degree of perception was Korean /(equation omitted)/ that is very unfamiliar to Polish subjects. Vowels that are not so different from the Ll sounds were perceived fairly well. Another important result is that Polish listeners seem to be more sensitive to lip rounding than to the height of the tongue. The role of the neighbouring sounds seems to be of a considerable importance, Depending on the preceding vowel, a sudden drop or rise in the degree of the perception was observed.

• 말소리와 음성과학
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• 제7권4호
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• pp.111-121
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• 2015

The present study examines the auditory boundary between Korean /o/ and /u/ on a synthesized vowel continuum by Chinese learners of Korean language. Preceding researches reported that the Chinese learners have difficulty pronouncing Korean monophthongs /o/ and /u/. In this experiment, a nine-step continuum was resynthesized using Praat from a vowel token from a recording of a male announcer who produced it in isolated form. F1 and F2 were synchronously shifted in equal steps in qtone (quarter tone), while F3 and F4 values were held constant for the entire stimuli. A forced choice identification task was performed by the advanced learners who speak Mandarin Chinese as their native language. Their experiment data were compared to a Korean native group. ROC (Receiver Operating Characteristic) analysis and logistic regression were performed to estimate the perceptual boundary. The result indicated the learner group has a different auditory criterion on the continuum from the Korean native group. This suggests that more importance should be placed on hearing and listening training in order to acquire the phoneme categories of the two vowels.

• 음성과학
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• 제4권1호
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• pp.19-34
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• 1998

The author collected and compared midsagittal, coronal, coronal oblique, and transversal images of Korean monophthongs /a, i, e, o, u, i, v/ produced by a healthy male speaker using 1.5 T MR, VISION. Area was measured by computer software after tracing the cross-section at different points along the tract. Results showed that the width of the oral and pharyngeal cavities varied compensatorily from each other on the midsagittal dimension. Formant frequency values estimated from the area functions of the seven vowels showed a strong correlation (r=0.978) with those analyzed from the spoken vowels. Moreover, almost all of 35 students who listened to the synthesized vowels from area data perceived the synthesized vowels as equivalent to the spoken ones. Movement of constriction points of vowel /u/ with wider lip opening sounded /i/ and led to slight changes in vowel quality. Jaw and tongue movement led to major volume variation with an anatomical limitation. Each comer vowel varied systematically from a somewhat constant volume of the average area. Thus, the author proposed that any simulation studies related to vocal tract area variation should reflect its constant volume. The results may be helpful to verify exact measurement of the vocal tract area through vowel synthesis and a simulation study before having any operation of the vocal tract.

• 음성과학
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• 제7권1호
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• pp.187-201
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• 2000

This study was done to investigate the English vowels in relation to the foreign accent. In this study, I also tried to find out the foreign accent of the English diphthong /o/ and front low vowel /${\ae}$/ when Koreans speak English. The reason why I chose these vowels is that these vowels, /o/ and /${\ae}$/, are difficult for Koreans to discern and pronounce. Koreans show a foreign accent in their pronunciation. In order to find out the reason for a Korean foreign accent, experiments were carried out with the help of acoustic instruments. According to the results of the experiment, Koreans showed a foreign accent in their English pronunciation of vowels in relation to their utterance positions. Americans showed a final lengthening effect but Koreans showed a final shortening effect. This means that Koreans showed a foreign accent in the final stressed syllable of a sentence. In addition to this, the duration of two English vowels, /o/ and /${\ae}$/, showed considerably different features between Koreans and Americans. In fact, in the pronunciation of the diphthong /o/, the tongue moves from one position to another. The two articulations of a diphthong can be described as the nucleus plus a glide. However, most Koreans have no idea of this phenomenon and pronounce the diphthongs like two separate monophthongs. This causes a great difference in the lengths of English diphthong /o/ between Koreans and Americans.

• 말소리와 음성과학
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• 제8권2호
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• pp.11-16
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• 2016

This study explores the phoneme distribution and syllable structure of entry words in the CMU English Pronouncing Dictionary to provide phoneticians and linguists with fundamental phonetic data on English word components. Entry words in the dictionary file were syllabified using an R script and examined to obtain the following results: First, English words preferred consonants to vowels in their word components. In addition, monophthongs occurred much more frequently than diphthongs. When all consonants were categorized by manner and place, the distribution indicated the frequency order of stops, fricatives, and nasals according to manner and that of alveolars, bilabials and velars according to place. These results were comparable to the results obtained from the Buckeye Corpus (Yang, 2012). Second, from the analysis of syllable structure, two-syllable words were most favored, followed by three- and one-syllable words. Of the words in the dictionary, 92.7% consisted of one, two or three syllables. This result may be related to human memory or decoding time. Third, the English words tended to exhibit discord between onset and coda consonants and between adjacent vowels. Dissimilarity between the last onset and the first coda was found in 93.3% of the syllables, while 91.6% of the adjacent vowels were different. From the results above, the author concludes that an analysis of the phonetic symbols in a dictionary may lead to a deeper understanding of English word structures and components.

• 음성과학
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• 제13권4호
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• pp.69-87
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• 2006

This study aims to describe the vowel system of present-day American English and to discuss some of its phonetic variations due to regional differences. Fifteen speakers of American English from various regions of the United States produced the monophthongs of English. The vowel duration and the frequencies of the first and the second formant were measured. The results indicate that the distinction between the vowels [c] and [a] has been merged in most parts of the U.S. except in some speakers from eastern and southeastern parts of the U.S., resulting in the general loss of phonemic distinction between the vowels. The phonemic merger of the two vowels can be interpreted as the result of the relatively small functional load of the [c]-[a] contrast, and the smaller back vowel space in comparison to the front vowel space. The study also shows that the F2 frequencies of the high back vowel [u] were extremely high in most of the speakers from the eastern region of the U.S., resulting in the overall reduction of their acoustic space for high vowels. From the viewpoint of the Adaptive Dispersion Theory proposed by Liljencrants & Lindblom (1972) and Lindblom (1986), the high back vowel [u] appeared to have been fronted in order to satisfy the economy of articulatory gesture to some extent without blurring any contrast between [i] and [u] in the high vowel region.

• 음성과학
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• 제13권3호
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• pp.67-82
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• 2006

The purpose of this experimental study is to investigate formant characteristics of Korean monophthongs spoken by Japanese learners and to compare the characteristics of vowels produced by the Japanese learners with those of the Korean native speakers. The data consisted of three categories: eight vowels in isolation, words including eight vowels in carrier sentences, and words including eight vowels in natural sentences. In this study, formant frequencies of the vowels were measured by Wave Surfer. It was assumed that the formant frequencies of the Korean vowels produced by the Japanese learners could be different from those of the Korean native speakers due to the influence of their own Japanese vowels. Results of this study showed that the Japanese learners had the difficulties to distinguish between the pairs /-/and /ㅜ/, /ㅓ/and /ㅗ/, and /ㅏ/and /ㅔ/. In Japanese vowels, F2 frequency value of /ㅜ/ was similar to that of the Korean /-/. It means that when the Japanese leaners produced Korean /ㅜ/, they might neutralize /-/ and /ㅜ/. Besides, there were not /ㅓ/and /ㅐ/ in Japanese vowels. Therefore, they tended to pronounce /ㅓ/ similar to /ㅗ/ which has the most similar formant frequency value with that of /ㅓ/, and /ㅐ/ was pronounced similar to /ㅔ/ for the same reason.

• 말소리와 음성과학
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• 제2권2호
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• pp.43-50
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• 2010

English vowels can be divided into monophthongs and diphthongs depending on the number of vocal tract shapes. Diphthongs are usually produced with more than one shape. This study attempts to collect acoustical data of English diphthongs published by Hillenbrand et al.(1995) online and to examine acoustic features of the diphthongs for phoneticians and English teachers. Sixty three American males and females were chosen after excluding those subjects with different target vowels or ambiguous formant tracks. The author used Praat to obtain the acoustical data systematically at eleven equidistant timepoints over the diphthongal segment. Obvious errors were corrected based on the spectrographic display of each diphthong. Results show that the formant trajectories of the diphthongs produced by the American males and females appeared quite similar. When the female formant values were uniformly normalized to those of the males, almost a perfect collapse occurred. Secondly, the diphthongal movements on the vowel space appeared not linear due to the coarticulatory gesture for the following consonant. Thirdly, the average duration of the diphthongs produced by the females was 1.156 times longer than that of the males while the pitch ratio between the two groups turned out to be 1.746 with a similar contour over measurement points. The author concludes that English diphthongs produced by various groups can be compared systematically when the acoustical values are obtained at proportional timepoints. Further studies will be desirable on the comparison of English diphthongs produced by native and nonnative speakers.