• MALSORI
• /
• no.45
• /
• pp.1-14
• /
• 2003

This paper criticizes S. Kim (1992), claiming that the perception of place cues in the reduced stop consonant clusters ('reducing' means 'cutting off' the acoustic silence in stop clusters) largely depends on the acoustic characteristics such as formant transition and noise frequency distribution of stop burst, rather than the closure duration time as advocated by S. Kim (1992). The claim is based on the perception test conducted upon 111 stimuli over 10 subjects. The finding is that, when the closure duration is cut off up to the point where only one stop is perceived, place of the second stop, not the first one, in the cluster is in most cases perceived regardless of the places of the first and second stops. It is likely that the place cues of the stop in the prevocalic position mask those in the postvocalic position.

• Proceedings of the KSPS conference
• /
• 1996.10a
• /
• pp.390-398
• /
• 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.

• Proceedings of the KSPS conference
• /
• 2005.11a
• /
• pp.189-192
• /
• 2005

This study investigates the asymmetry effect between acoustics and perception. The examined cues are closure duration, closure voicing, VOT, release, pre-vowel duration, post-vowel duration. Five native speakers of English and 30 Korean college students participated in the present study. The results showed that high level Korean English learners parallels native speakers in their responses, while mid and low level Korean learners are substantially different from natives.

• MALSORI
• /
• no.33_34
• /
• pp.1-10
• /
• 1997

Korean stop consonants are well known for their tripple distinction. In word initial position lax, tense and aspirated consonants are all voiceless. They are differentiated by the degree of tension, aspiration and VOT(voice onset time). But in intervocalic position, lax consonants become voiced. In this study I compare the acoustic features of Korean intervocalic lax and tense stops. The closure duration of lax stops is shorter than that of tense consonants. The preceding vowel length is longer in tan than that in tense consonants. I modify the above acoustic characteristics by an experimental methods. For example, I shorten the closure duration of intervocalic tense stops by 5 steps. r also do auditory tests which will show us listener's reaction on the above examples. And do the same job with the preceding vowels. According to the auditory test, the closure duration does an important role in differentiating Korean intervocalic lax and tense stops. But the preceding vowel length has almost nothing to do with the distinction between lax and tense stops. So I conclude that acoustic features also have hierarchy. Some features have categorical characteristics and others don't.

• MALSORI
• /
• no.47
• /
• pp.31-49
• /
• 2003

This paper investigates phonation types of Malay plosives and compares Malay plosives with Korean ones in terms of VOT, F0, duration of closure, and durations of the preceding and following vowels. This study is significant in that it specifies phonetic characteristics of phonation types of the two languages and provides phonetic bases for teaching and learning either of the two languages. The results showed that Malay voiceless plosives are greater than voiced ones in VOT, F0, duration of closure, but the other way in durations of the preceding and following vowels. Comparison of the two languages, particularly in terms of the distribution of VOT, indicates that Malay voiceless plosives are close to Korean fortis plosives.

• Clinical and Experimental Pediatrics
• /
• v.53 no.4
• /
• pp.579-584
• /
• 2010

Purpose : The number of the repatriated Korean students who had overseas study at early ages is increasing. They received foreign education, they can speak international languages, but they have many difficulties in articulation and intonation of the Korean language. This study aims to measure closure and aspiration duration, length of consonants, length of subsequent vowels, and ratio of consonants against subsequent vowels in vowel-consonant-vowel (VCV) syllables. Methods : This study compares the acoustic and phonetic characteristics of repatriated and native students, the ratio of articulation error of Korean plosives, the closure and aspiration duration, and the ratio of the aspiration duration against the closure duration. Results : The ratio of articulation error of Korean plosives between repatriated and native students is 19% and 2%, respectively. The closure duration was significantly longer in repatriated students than in native students. The aspiration duration was significantly longer in repatriated students than in native students. No difference was found in the ratio of aspiration duration against closure duration between the native and repatriated students. Conclusion : This study can be a good reference for estimating the phonetic difficulties of Korean elementary students who had overseas study at early ages.

• Speech Sciences
• /
• v.10 no.2
• /
• pp.207-221
• /
• 2003

Phonetic voicing does not support the phonological distinction of voiced/voiceless in English stops. The present study is aimed at defining the nature of voicing of English voiced stops. A review of the literature reveals that the voicing is position-conditioned and its length is notably inconsistent relative to the closure duration. No consistent relationships are found between vocal fold adduction and glottal pulsing in initial position. Stress reduced the voicing, etc. The hypothesis for experiments was: (1) active voicing: stress generates longer (stronger) voicing during the closure duration of a voiced stop; (2) passive voicing: stress induces shorter (weaker) voicing during the closure. Instead the voiced stop becomes more voiced when the preceding vowel (syllable) is stressed. The literature review and the results of two experiments comparing English and Slovakian suggested that the voicing of English voiced stops is passive (i.e., a coarticulation of glottal pulsing for adjacent vowels-syllables) and should be distinguished from active voicing in some other languages.

• Journal of the Korean Institute of Intelligent Systems
• /
• v.18 no.2
• /
• pp.223-229
• /
• 2008

In this paper. we propose the real-time vision system which judges drowsiness driving based on levels of drivers' fatigue. The proposed system is to prevent traffic accidents by warning the drowsiness and carelessness using face-image analysis and fuzzy logic algorithm. We find the face position and eye areas by using fuzzy skin filter and virtual face model in order to develop the real-time face detection algorithm, and we measure the eye blinking frequency and eye closure duration by using their informations. And then we propose the method for estimating the levels of drivel's fatigue based on measured data by using the fuzzy logic and for deciding whether drowsiness driving is or not. Finally, we show the effectiveness and feasibility of the proposed method through some experiments.

• Phonetics and Speech Sciences
• /
• v.14 no.4
• /
• pp.11-17
• /
• 2022

This study investigates closure durations of Korean stops in terms of laryngeal contrasts, places of articulation, and three positions within words. Twenty-two Korean speakers produced the nonsense words containing Korean stops found in word-initial and word-final positions and between vowels. The statistical results showed that the closure durations differed significantly by laryngeal contrast and place of articulation. In addition, the differences by position within words were marginally significant. The closure durations were in the order of lenis < aspirated < fortis stops by laryngeal contrast, velar < alveolar < bilabial stops by place of articulation, and word-final < word-initial < between vowels by positions within words. The laryngeal contrasts were neutralized in word-final position as per coda neutralization in Korean phonology. This study shows that closure durations should be considered a valuable phonetic cue to identify stops on par with voice onset time and f0.

• Speech Sciences
• /
• v.5 no.2
• /
• pp.17-26
• /
• 1999

It has been claimed that Korean mid-vocalic voiceless unaspirated lax stops are phonetically realized with voicing throughout the oral closure phase. Acoustic measurements were undertaken to examine the claim with four Korean native speakers using /$V_1CV_2$/ words where the vowel ($V_1\;=\;V_2$) was /i, a, u/ and the C was voiceless unaspirated lax stops /p, t, k/. Findings: (1) During mid-vocalic stops /k/ and /p/ the vowel /u/ was accompanied generally by a significant increase in voice cessation time as percentage of the oral closure interval (PCT) than the vowel /a/, regardless of subjects, whereas in mid-vocalic alveolar stop /t/ the effects of vowels on PCT were subject-dependent, (2) The effects of vowels on PCT were significantly greater in mid-vocalic /k/ than /p/, regardless of subjects, (3) The mean PCT, averaged across six tokens, ranged from 17% to100%, giving overall mean 61% in which the standard deviation was ${\pm}30$, and (4) Overall % of the total of mid-vocalic unaspirated lax stops were produced with a substantial period of devocing and voicing lag. Considering these results, it is difficult to agree with the existing claims that Korean voiceless unaspirated lax stops are phonetically realized with voicing throughout the oral closure phase. Other phonetic variables, including the durations of pre/post-stop vowels, voice onset time, voice cessation time, and the duration of oral closure, were measured.