• 대한음성학회:학술대회논문집
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• 대한음성학회 1996년도 10월 학술대회지
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• pp.53-69
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• 1996

Much research has been done on the rues differentiating the three Korean stops in word initial position. This paper focuses on a more neglected area: the acoustic cues differentiating the medial tense and lax unaspirated stops. Eight adult Korean native speakers, four males and four females, pronounced sixteen minimal pairs containing the two series of medial stops with different preceding vowel qualities. The average duration of vowels before lax stops is 31 msec longer than before their tense counterparts (70 msec for lax vs 39 msec for tense). In addition, the average duration of the stop closure of tense stops is 135 msec longer than that of lax stops (69 msec for lax vs 204msec for tense). THESE DURATIONAL DIFFERENCES ARE 50 LARGE THAT THEY MAY BE PHONOLOGICALLY DETERMINED, NOT PHONETICALLY. Moreover, vowel duration varies with the speaker's sex. Female speakers have 5 msec shorter vowel duration before both stops. The quality of voicing, tense or lax, is also a cue to these two stop types, as it is in initial position, but the relative duration of the stops appears to be much more important cues. The duration of stops changes the stop perception while that of preceding vowel does not. The consequences of these results for the phonological description of Korean as well as the synthesis and automatic recognition of Korean will be discussed.

• 말소리와 음성과학
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• 제9권3호
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• pp.57-65
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• 2017

The current study explored how Korean-speaking children processed the multiple acoustic cues (VOT and f0) for the stop laryngeal contrast (/t'/, /t/, and /$t^h$/) and examined whether individual perceptual strategies could be related to a general cognitive ability performing executive functions (EF). 15 children (aged from 7 to 8) participated in the speech perception task identifying the three Korean laryngeal stops (3AFC) on listening to the auditory stimuli of C-/a/ with synthetically varying VOT and f0. They completed a series of EF tasks to measure working memory, inhibition, and cognitive shifting ability. The findings showed that children used the two cues in a highly correlated manner. While children utilized VOT consistently for the three laryngeal categories, their use of f0 was either reduced or enhanced depending on the phonetic categories. Importantly, the children's processing strategies of a f0 suppression for a tense-aspirated contrast were meaningfully associated with children's better cognitive abilities such as working memory, inhibition, and attentional shifting. As a preliminary experimental investigation, the current research demonstrated that listeners with inefficient processing strategies were poor at the EF skills, suggesting that cognitive skills might be responsible for developmental variations of processing sub-phonemic information for the linguistic contrast.

• 말소리와 음성과학
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• 제11권2호
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• pp.15-21
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• 2019

Korean and English are both known to show on-focus pitch range expansion and post-focus pitch range compression (PFC). But it is not clear if this prosodic similarity would make it easy for Korean speakers to learn English focus prosody. In the present study, we conducted a production experiment using phone number strings to examine whether Korean learners of English produce a native-like focus prosody. Korean learners of English were classified into three groups (advanced, intermediate and low) according to their English proficiency and were compared to native speakers. Results show that intermediate and low groups of speakers did not increase duration, intensity, and pitch in the focus positions, nor did they compress those cues in the post-focus positions. Advanced speakers noticeably increased the acoustic cues in the focus positions to a similar extent as native speakers. However, their performance in post-focus positions was quite far from that of native speakers in terms of pitch and excursion size. These results thus demonstrate a lack of positive transfer of focus prosody from Korean to English in L2 learning, and learners may have to relearn it from scratch, which is consistent with a previous finding. More importantly, the results provide further support for the view proposed in other works that acoustic properties of PFC were not easily transferred from one language to another.

• 말소리와 음성과학
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• 제13권4호
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• pp.9-21
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• 2021

본 연구는 한국어 평음과 기음 대조에 초점을 맞춘 지각 훈련을 통해 한국어 학습자들이 L2 폐쇄음을 대조하는 음향 신호의 지각 가중치를 모국어 값의 방향으로 개선하는지 고찰하였다. 중국어가 모국어인 한국어 학습자 19명과 지각 훈련을 진행한 한국어가 모국어인 교사 2명이 실험에 참가하였다. 사전 테스트 결과에 따라 훈련 집단과 비훈련 집단으로 나누었고, 훈련 집단만 5일 동안 지각 훈련을 진행하였다. 폐쇄음 신호의 지각 가중치를 추정하기 위해 음향 신호를 체계적으로 조작한 자극으로 사전 및 사후 테스트를 시행했다. 개별 학습자들의 테스트 결과에 대해 이분형 로지스틱 회귀 분석을 시행해, 말소리 대조를 지각하는 데에 해당 음향 신호를 사용한 가중치를 추정하는 지각 β 계수 값을 계산하였다. 두 폐쇄음을 구별하는 주요 신호인 F0의 지각 계수에 대해, 훈련 집단은 사전 테스트 대비 사후 테스트에서 평균 0.451의 통계적으로 유의미한 증가를 보인 반면 비훈련 집단은 유의미하지 않은 0.246의 증가를 나타냈다. 그러나 지각 훈련 후 F0 사용의 변화 패턴이 개별 학습자들 간에 다양하게 나타났다.

• 말소리와 음성과학
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• 제4권1호
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• pp.13-20
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• 2012

A lax stop in Korean, one of the three laryngeal contrastive stops, has undergone a sound change in terms of its acoustic properties. Prior production studies described this recent lax stop as being differentiated from tense and aspirated stops primarily by fundamental frequencies (f0). And, the acoustic property of voice onset time (VOT) further separates tense stops from lax and aspirated stops. The current research explores how these two major acoustic parameters of f0 and VOT cue the three stop categories in Korean adult listeners' perception. Thirty-one native speakers of Korean participated in two experimental tasks: categorization judgment and within-category goodness ratings. Two sets of audio stimuli were prepared by synthesizing English and Korean male speakers' CV productions. The findings showed that while f0 cues listeners to lax stops as production patterns would predict, VOT were closely related to listeners' categorization and goodness ratings of lax stops. This suggests that accurate characterizations of the recent lax stop category need to be based on Korean speakers' perceptual behavior as well as production patterns.

• 말소리와 음성과학
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• 제14권3호
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• pp.1-9
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• 2022

The current study examined English-speaking adult learners' production and perception of L2 Korean stops (/t/ or /t'/ or /t^h/) to investigate whether the two modalities are linked in utilizing voice onset time (VOT) and fundamental frequency (F0) for the L2 sound distinction and how the learners' L2 proficiency mediates the relationship. Twenty-two English-speaking learners of Korean living in Seoul participated in the word-reading task of producing stop-initial words and the identification task of labelling CV stimuli synthesized to vary VOT and F0. Using logistic mixed-effects regression models, we quantified group- and individual-level weights of the VOT and F0 cues in differentiating the tense-lax, lax-aspirated, and tense-aspirated stops in Korean. The results showed that the learners as a group relied on VOT more than F0 both in production and perception (except the tense-lax pair), reflecting the dominant role of VOT in their L1 stop distinction. Individual-level analyses further revealed that the learners' L2 proficiency was related to their use of F0 in L2 production and their use of VOT in L2 perception. With this effect of L2 proficiency controlled in the partial correlation tests, we found a significant correlation between production and perception in using VOT and F0 for the lax-aspirated stop contrast. However, the same correlation was absent for the other stop pairs. We discuss a contrast-specific role of acoustic cues to address the non-uniform patterns of the production-perception link in the L2 sound learning context.

• 말소리와 음성과학
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• 제5권4호
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• pp.81-90
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• 2013

This study explored how Korean L2 learners of English utilize multiple acoustic cues (VOT and F0) in perceiving and producing the English alveolar stop with a voicing contrast. Thirty-four 18-year-old high-school students participated in the study. Their English proficiency level was classified as either 'high' (HEP) or 'low' (LEP) according to high-school English level standardization. Thirty different synthesized syllables were presented in audio stimuli by combining a 6-step VOTs and a 5-step F0s. The listeners judged how close the audio stimulus was to /t/ or /d/ in L2 using a visual analogue scale. The L2 /d/ and /t/ productions collected from the 22 learners (12 HEP, 10 LEP) were acoustically analyzed by measuring VOT and F0 at the vowel onset. Results showed that LEP listeners attended to the F0 in the stimuli more sensitively than HEP listeners, suggesting that HEP listeners could inhibit less important acoustic dimensions better than LEP listeners in their L2 perception. The L2 production patterns also exhibited a group-difference between HEP and LEP in that HEP speakers utilized their VOT dimension (primary cue in L2) more effectively than LEP speakers. Taken together, the study showed that the relative cue-weighting strategies in L2 perception and production are closely related to the learner's L2 proficiency level in that more proficient learners had a better control of inhibiting and enhancing the relevant acoustic parameters.

• 한국음향학회지
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• 제13권5호
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• pp.69-76
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• 1994

국어 자음을 단어내 음운환경별로 실험해 본 결과, 국어의 자음변이 규칙이 반영된 일관성있는 음가변화를 발견하였다. 발견된 음가변화는, ⅰ) 장애음의 길이는 모음간보다 단어초가 길고, ⅱ) 공명음의 길이는 단어초와 모음간보다 단어말이 길며, ⅲ) /ㄹ/의 F2와 F3는 모음간이 낮고 단어말은 높다는 것이다.ⅰ) 이들 음향특징의 근거가 되는 국어의 자음변이 규칙은, ⅰ) 평음의 유성화 현상, ⅱ) 음절말 불파음화 현상, ⅲ) 단어초 기음화 현상, ⅳ) /ㄹ/ 음소의 [r]과 [l] 교체현상이다. 본 실험결과 제시된 변화값은 음성인식 및 합성에 응용될 때 인식의 정확성과 합성의 자연성을 향상시킬 수 있다.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1991년도 춘계학술대회
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• pp.39-42
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• 1991

Two types of speech signal processores (SSP) for cochlea prosthesis are designed. One is designed using cochlear model and the other is designed using Information (formant, pitch, intensity) extraction method. For these, cochlear model and acoustic information extraction method are proposed. The result shows SSP of cochlear model type contain more acoustic cues than that of information extraction type.

• 대한의용생체공학회:의공학회지
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• 제12권4호
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• pp.285-294
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• 1991

Two types of the speech signal processores (SSP) for the cochlear a prosthesis are designed. One is designed using the cochlear model and the other is designed using the information (formant, pitch, intensity) extraction method. For these, some cochlear model and acoustic information extraction method are proposed. The result shows the SSP of the cochlear model type contain more acoustic cues than that of information extraction type. On the other hand, stimulus signal is clear and algorithm is simple in the SSP of the information ex traction type.