• 대한음성학회:학술대회논문집
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• 대한음성학회 2005년도 춘계 학술대회 발표논문집
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• pp.21-24
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• 2005

This paper presents durational characteristics of Korean Lombard speech using data, which consist of 500 Lombard utterances and 500 normal utterances of 10 speakers (5 males and 5 females). Each file was segmented and labeled manually and the duration of each segment and each word was extracted. The durational change of Lombard effect in comparison with normal speech was analyzed using a statistical method. The results show that the duration of words with Lombard effect is increased in comparison with normal style, and that the average unvoiced consonantal duration is reduced while the average vocalic duration is increased. Female speakers show a stronger tendency towards lengthening the duration in Lombard speech, but without statistical significance. Finally, this study also shows that the speakers of Lombard speech could be classified according to their different duration rate.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2003년도 5월 학술대회지
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• pp.219-222
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• 2003

In this paper, we study the usage of phoneme duration information for rejection garbage sentence. First, we build a phoneme duration modeling in a speech recognition system based on dicicion tree state tying, We assume that phone duration has a Gamma distribution. Next, we build a verification module in which word-level confidence measure is used. Finally, we make a comparative study on phoneme duration with speech DB obtained from the live system. This DB consistes of OOT(out-of-task) and ING(in-grammar) utterences. the usage of phone duration information yields that OOT recognition rate is improved by 46％ and that another 8.4％ error rate is reduced when combined with utterence verification module.

• 음성과학
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• 제11권3호
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• pp.23-36
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• 2004

Many languages show reverse durational variation between preceding vowel and following voiced/voiceless (lax/tense) consonants. This study investigated the likely effects of phoneme type (tense vs. lax) on the timing structure (duration of syllable, word, phrase and sentence) of Korean. Three rates of speech (fast, normal, slow) applied to stimuli with the target word /a-Ca/ where /C/ is one of /p, p', $p^h$/. The type (tense/lax) of /C/ caused marked inverse durational variations in the two syllables /a/ and /Ca/ and highly different durational ratios between them. Words with /p', $p^h$/ were significantly longer than that with /p/, which contrasts with many other languages where such pairs of words have a similar duration. The differentials between words remained up to the phrase and sentence level, but in general the higher linguistic units did not statistically differ within each level. Thus, the phrase is suggested as a compensatory unit of phoneme type effects in Korean. Different rates did not affect the general tendency. Distribution of time variations (from normal to fast and slow) to each syllable (/a/ and /Ca/) was also observed.

• 대한음성학회지:말소리
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• 제63호
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• pp.67-84
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• 2007

Verb phrase could have two different meanings according to which is followed after verb; adverb or preposition. The meaning of 'verb+adverb' is deduced from a figurative meaning which is idiomatic expression, and 'verb+preposition' is interpreted as the literal meaning. The purpose of this study is to observe how English native speakers and Korean leaners of English distinguish two sentences of the same word strings with acoustic cues like pause and duration. According to the result, as pause was used for meaning distinction, it was likely that the pause length preceding prepositions was longer than that of following adverbs. To distinguish two sentences of the same word strings, all participants seemed to use pause, verb lengthening and adverb/preposition lengthening. Among them, there is a hierarchical significance; in sequence, pause, verb lengthening, adverb/preposition lengthening.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2007년도 한국음성과학회 공동학술대회 발표논문집
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• pp.114-118
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• 2007

The current study investigates the degree to which various prosodic cues at the boundaries of a prosodic phrase in Korean (Accentual Phrase) contributed to word segmentation. Since most phonological words in Korean are produced as one AP, it was hypothesized that the detection of acoustic cues at AP boundaries would facilitate word segmentation. The prosodic characteristics of Korean APs include initial strengthening at the beginning of the phrase and pitch rise and final lengthening at the end. A perception experiment revealed that the cues that conform to the above-mentioned prosodic characteristics of Korean facilitated listeners' word segmentation. Results also showed that duration and amplitude cues were more helpful in segmentation than pitch. Further, the results showed that a pitch cue that did not conform to the Korean AP interfered with segmentation.

• 한국음향학회지
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• 제19권6호
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• pp.28-33
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• 2000

낱말 내에서 선행음절말-후속음절초로 연이어 나타나는 일종의 쌍자음(geminate)의 지속시간 차이를 고찰하고자 한다. (ㅁ-ㅁ) 연쇄와 (ㄴ-ㄴ) 연쇄를 중심으로 논의하였다. 한 낱말 내에서 선행하는 양순 비음 (ㅁ)과 이를 뒤따르는 양순 비음(ㅁ) 사이에 통계적으로 유의한 차이는 없다고 볼 수 있으나, 선행하는 자음의 지속시간이 약간 짧아지는 경향이 관찰되었다. 치조비음 (ㄴㄴ) 연쇄의 경우, 전반적으로, 한 낱말 내에서 선행하는 치조 비음과 이를 뒤따르는 치조 비음 사이에는 통계적으로 차이가 있으며, 선행하는 자음의 지속시간이 좀 더 길어지는 경향이 있다고 정리할 수 있다.

• 대한음성학회지:말소리
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• 제40호
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• pp.51-63
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• 2000

There are sentences where sentence stress is imposed on a specific word. These sentences are called 'focused sentences'. The purpose of this paper is to investigate the variation of pitch, duration, amplitude in focused words. It is noted that pitch of a focused word is higher than that of unfocused words irrespective of the accentual pattern, and that contour tones such as HL or LH are realized longer when these tones appear in focused words. Not only the noun but also the following particle like '-boda' is higher when these words are in focus. Hence pitch is proved to be the most salient prosodic feature of the focused sentence.

• 음성과학
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• 제7권2호
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• pp.139-155
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• 2000

The aim of this research is to investigate acoustic characteristics of three different types of Korean Stops-plain, tensed, and aspirated-, and employ these as a base to determine which one(s) can be used as perceptual cues. In this paper, we have examined acoustic characteristics of Korean Stops, especially voice onset time(VOT), closure duration(CD), degree of pitch of following vowels and differences in the intensity of the Stops build-up after the onset of voicing. From the above characteristics, differences can be made between word-initial and word-medial positions. That is to say, in word-initial position, the three Korean Stops are distinguished by VOT and pitch, whereas in word-medial by CD, VOT and pitch. However, the acoustic characteristics do not have the same value as perceptual cues. In both word-initial, and medial positions, the immediately following vowels play the most important role in perceiving Korean Stops. And in case of word'-medial positions,. CD and VOT also play important perceptual roles. In order to have a more fine-grained distinction among Korean Stops, we think future research should be done to investigate which factor(s) of the following vowels is/are the most determinative perceptual cue(s). However, based on our investigation, we may conclude that it is highly plausible that pitch can be one of the most important perceptual cues when distinguishing the three Korean Stops.

• 음성과학
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• 제2권
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• pp.135-147
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• 1997

This thesis describes pronunciation differences of vowel lengths between Koreans and Americans speaking English words and sentences. This study also analizes the reasons for these differences with the help of acoustic instruments. Sixteen sentences and eight words were selected as the experimental material. The informants for this study were 9 males; 3 Americans and 6 Koreans, who were asked to pronounce the test words and sentences five times. In this study, the acoustical analysis to measure duration was done through computer digital techniques. According to the results of the experiment, duration of 8 English vowels pronounced between Koreans and Americans shows very different features. When Koreans pronounce English vowels, the duration of the stressed vowel in the sentence-final position is much shorter than in other positions, such as in the sentence-initial and in word position. On the contrary, when Americans pronounce English vowels, the duration of the stressed vowel in the sentence-final position is much longer than in other positions. If the correlation between length and stress were to be studied in a more detailed manner, it would give fundamental help to the study of relation between stress and length.

• 대한음성학회:학술대회논문집
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• 대한음성학회 1996년도 10월 학술대회지
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• pp.390-398
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• 1996

Acoustic analysis study was performed on 20 normal subjects by speaking nonsense syllables composed of Korean bilabial stops(/p, $p^{*}$/, ph/) and their Preceding and/or following vowel /a/(that is, [pa, $p^{*}a$, pha, apa, $ap^{*}a$, apha]) with an ultraminiature pressure sensor in their mouths. Speech materials were phonated twice, once with a moderate voice, another time with a loud voice. The acoustic signal and intraoral pressure were recorded simultaneously on computer. By these procedures, we were to measure the intraoral pressure, closure duration and VOT of Korean bilabial stops, and to compare the values one another according to the intensity of phonation and the position of the target consonants. Intraoral pressure was measured by the peak intraoral pressure value of its wave; closure duration by the time interval between the onset of intraoral pressure build-up and the burst meaning the release of closure; Voice onset time(VOT) by the time interval between the burst and the onset of glottal vibration. Heavily aspirated bilabial stop consonant /ph/ showed the highest intraoral pressure value, unaspirated /p$^{*}$/, the second, slightly aspirated /p/, the lowest. The syllable initial bilabial stops showed higher intraoral pressure than word initial stops, and the value of loudly phonated consonants were higher than moderate consonants. The longest closure duration period was that of /$p^{*}$/ and the shortest, /p/, and the duration was longer in word initial position and in the moderate voice. In VOT, the order of the longest to shortest was /ph/, /p/, /$p^{*}$/, and the value was shorter when the consonant was in intervocalic position and when it was phonated with a loud voice.