• 음성과학
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• 제2권
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• pp.149-158
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• 1997

An Electropalatographic (EPG) study was made to investigate the articulatory distinction of three series of Korean stops according to tensity and the articulatory mechanism associated between tensity and coarticulatory effects. The results indicated that tensity of Korean stops is closely related to contact width and duration of complete closure, and that coarticulatory vocalic effects vary inversely with the degree of contact width and duration of complete closure.

• 한국정보처리학회논문지
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• 제4권6호
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• pp.1531-1540
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• 1997

본 논문에서는 발화속도 측정과 이를 통한 보상방법을 통하여 성능 향상된 한국어 연속음 인식 시스템을 제안한다. 연속음 인식은 다양한 조음화 현상과 발화속도의 변화로 인하여 고립단어 인식에 비하여 어렵다. 따라서, 연속음 인식을 위해서는 조음화 현상과 발화속도의 변화를 모델링할 수 있는 방법이 필요하다. 본 논문에서는 발화속도를 포만트의 변화율로서 측정하였고, 이 정보를 이용하여 빠른 발화에서는 상대적으로 많은 특징벡터를 발생시켜 보상을 시도하였다. 또한 조음화 현상을 모델링하기 위하여 한국어의 다이폰 집합을 514개로 정의하였고, 훈련을 위한 음성 DB론느 ETRI의 445 단어 DB를 사용하였다. 이러한 방법을 결합한 한국어 연속음 인식기를 DHMM (Discrete Hidden Markov Model)으로 구현하여 인식률이 향상됨을 보였다.

• 음성과학
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• 제4권1호
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• pp.135-145
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• 1998

An Electropalatographic (EPG) study was conducted to investigate the articulatory characteristics which determine the, distinction between the Korean lax fricative [s] and tense fricative [s']. This study also intended to test if an increase in the degree of tensity (lax fricative [s] < tense fricative [s']) induces a decrease in coarticulatory vocalic effects. The results indicated that the increase in the tensity of Korean fricatives is closely related to the increase in the narrowness of the groove width (wider contact at the place of articulation), the forward shifting in the place of articulation, and the longer duration of the constriction (longer maintenance in the manner of articulation). It was also found that coarticulatory vocalic effects on Korean fricatives are affected by Recasens' two rules of constraint (1983) : spatial and temporal constraints.

• 음성과학
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• 제7권3호
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• pp.11-19
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• 2000

The present electropalatographic study reports the production of the allophones. i.e., [l] and [r], of Korean tap /r/ and their coarticulatory characteristics in /$C{\'{a}}r#g$/ and /$C{\'{a}}r#i$/ sequences. The finding that tap /r/ involves a complete oral closure with less lingual contact, i.e., apico-frontalveolar coupling. than lateralized /r/ which involves apico-bladealveolar coupling and tongue dorsum lowering for adequate airflow through either side and/or both of the tongue body suggests that the two allophones of the tap /r/ have different lingual gestures. Moreover. in comparison with the tap. the lateral exerts longer lingual contacts. The mean ratio between them is 3.7. In the sequences /Car#g/. the two adjacent antagonistic segments (i.e., /r/ and /g/) show mutual coarticulation effects taking on features of adjacent segment. but either of them is precisely constrained without blocking the formation of involved major lingual gestures for the other segment. In sequences /Car#i/ occurs anticipatory V-to-C coarticulation but not vocalic carryover effects. In both sequences. the allophones reveal insignificant wordinitial consonantal carryover coarticulatory effects and insignificant speaker-specific lingual contacts.

• 말소리와 음성과학
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• 제6권4호
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• pp.109-115
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• 2014

Fricated nuclei in Nuosu Yi were found to be more correctly described as fricated vowels, rather than syllabic fricatives due to the presence of clear formant structures typical of front vowels. In this exploratory study, two types of fricated nuclei were examined: retroflex "yr" and non-retroflex "y". The retroflex nucleus "yr" had higher F1 and lower F3 than non-retroflex "y", indicating a lower tongue height. On the other hand, F2 was found to correlate not with nucleus retroflexion, but instead with onset consonant retroflexion: F2 was higher following retroflex onsets, in both vowels. This effect was persistent through the entire vowel, suggesting a phonological effect, rather than a coarticulatory one. Interpretation of the F2 results require accompanying articulatory data since the usual coupling of F2 and tongue backness does not always hold for retroflex vowels. Examining the articulation of the fricated nuclei in Nuosu Yi is a direction for future research.

• 음성과학
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• 제7권4호
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• pp.107-121
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• 2000

In this paper, I investigate the acoustic correlates of a vowel's coarticulatory dynamics manifested in preceding and following consonants along two dimensions of the vocal tract: place of articulation and degree of constriction. Two dimensional coarticulation is not necessarily executed either concomitantly or proportionally, and the modification induced by coarticulation with a vowel in CVC structures is merely restricted to the CV portion; that is, the prevocalic consonant is modified solely in its constriction location. This is consistent with the observation that C-to-V place assimilation does not accompany consonant lenition in phonology, which suggests that phonetic nature is effectively reflected in phonological patterns.

• 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.

• 말소리와 음성과학
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• 제6권1호
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• pp.3-10
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• 2014

This study investigated whether Korean vowels, /ɨ/ and /u/, are distinctively perceived after a labial consonant given the fact that native and Sino-Korean nouns showed only vowel /u/ after a labial consonant while this pattern was massively broken by the recent introduction of loanwords. For this purpose, a perception experiment was conducted with $V_1C_1V_2$ sequences in which different vowels /a, i, u/ and consonants /p, t, k/ occurred in $V_1$ and $C_1$ before the target $V_2$, /ɨ/ and /u/. The data was produced by six speakers each from two different age groups, Age20 and Age40/50 in the read speech style. The results showed that consonant /p/ attracted significantly more responses of /u/ from /VCɨ/ sequences and significantly less responses of /u/ from /VCu/ sequence than the other consonants did in both age groups. Furthermore, Age20 group showed significantly less percentage of /u/ responses than Age40 group when the preceding consonant was /p/ regardless of the target vowel. We suggest therefore that unlike the traditional belief of labial assimilation, there is neutralization after a labial consonant in which vowels /ɨ/ and /u/ are often realized as any sound between two vowels, /ɨ/ and /u/. That is, this vowel change is not categorial but it rather produces an ambiguous stimulus which attracts different responses from different listeners. Ambiguous stimulus was produced due to coarticulatory efforts in speech production and perceptual compensation. We also argue that there is generational difference such that Age40/50 group speakers showed stronger tendency to produce /u/ after a labial consonant regardless of whether the target vowel was /ɨ/ or /u/.