• 음성과학
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• 제8권4호
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• pp.193-206
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• 2001

The purpose of this experimental study was to investigate characteristics of English vowels uttered by Korean regional dialect speakers. Ten English mono-syllabic words, and eight Korean mono-syllabic words, were uttered six times by nine female graduate students from three areas: Seoul, Yongnam and Honam. Formant frequencies were measured from sound spectrograms made by the PC Quirer. Results showed that Seoul dialect speakers uttered English vowels more similar to those uttered by English native speakers than did the other dialect speakers. In particular, Yongnam dialect speakers have articulatory problems pronouncing the back vowels(/u/, /$\upsilon$/, /c/), while Honam dialect speakers have problems pronouncing the front vowels(/i/. /I/, /$\varepsilon$/, /$\ae$/). Even though each group has different problems pronouncing English vowels, Korean speakers generally have difficulty in discriminating tense vowels(/i/ and /u/) from the lax vowels(/I/ and /$\upsilon$/). It appears that the width of Korean speakers' articulatory movements is comparatively narrower than those of native English speakers.

• 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.

• 음성과학
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• 제12권2호
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• pp.7-16
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• 2005

The purpose, this experimental study was to identify pronunciation difficulties between male and female Korean speakers in their articulation of English vowels. Ten English mono-syllabic words were spoken six times by six male and six female college students. Formant frequencies were measured from sound spectrograms made by Pitch Works. Results show that Korean female speakers uttered English vowels more similar to those uttered by English native speakers than did Korean male speakers. While Korean male speakers could not readily distinguish between /i/ and /I/, /u/ and /v/, and /$\epsilon$/ and /ae/, respectively, Korean female speakers had difficulty only with /$\epsilon$/ and /ae/. The tentative results suggests that on the whole Korean speakers have difficulty in discriminating tense vowels from lax vowels, and they also have articulatory problems pronouncing low and back vowels such as /ae/. /a/ and /c/.

• 음성과학
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• 제7권3호
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• pp.99-108
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• 2000

The purpose of this experimental study was to investigate characteristics of English vowels as spoken by Korean speakers. Ten English mono-syllabic words were spoken six times by six male college students who were born and raised in Seoul. Formant frequencies were measured from sound spectrograms made by the PC Quirer. Results showed that Korean speakers similarly pronounced /i/ and /I/, /u/ and /$\upsilon$/, and /$\varepsilon$/ and /${\ae}$/ respectively. It seems that Korean speakers can not differentiate tense vowels(/i/, /u/) from lax vowels(/i/, /$\upsilon$/) and pronounce low vowels such as /${\ae}$/, /a/, /c/ clearly. It is necessary that Korean speakers practice the correct movements of the jaw, tongue, and lips when they pronounce English vowels.

• 말소리와 음성과학
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• 제2권3호
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• pp.37-46
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• 2010

This study investigates acoustic characteristics of English and Korean voiceless sibilant fricatives as they appear before the three vowels, /i/, /$\alpha$/ and /u/. Three measurements - duration, center of gravity and major spectral peak - are employed to compare acoustic properties and vowel effect for each fricative sound. This study also investigates the question of whether Korean sibilant fricatives are acoustically similar to the English voiceless alveolar fricative /s/ or to the palato-alveolar /$\int$/. The results show that in the duration of frication noise, English /$\int$/ is the longest and Korean lax /s/ the shortest of the four sounds. It is also observed that English alveolar /s/ has the highest value, whereas Korean /s/ shows the lowest value in the frequency of center of gravity. In terms of major spectral peak, while English /s/ reveals the highest frequency, English /$\int$/ shows the lowest value. In addition, evidence indicates that there is a strong vowel effect in the fricative sounds of both languages, although the vowel effect patterns of the two languages are inconsistent. For instance, in the major spectral peak, both Korean lax /s/ and tense /$s^*$/ show significantly higher frequencies before the vowel /$\alpha$/ than before the other vowels, whereas both English /s/ and /$\int$/ exhibit significantly higher frequencies before the vowel /i/ than before the other vowels. These results indicate that Korean sibilant fricatives are acoustically distinct from both English /s/ and /$\int$/.

• 말소리와 음성과학
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• 제12권3호
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• pp.15-23
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• 2020

This study examines the duration of Korean lax and tense stops in the prosodic word-medial position, their interactions with nearby segments, and the phonological implications of these interactions. It first examines the lengthening of consonants at the function of the short lax stop. Experiment 1 shows that the sonorant C1 is significantly longer before a short lax stop C2 than before a long tense stop. Experiment 2 shows that the short lax stop C1 cancels the contrast between the lax and tense obstruent at C2, making them appear as long tense obstruents (Post-Stop Tensing Rule). We suggest that such lengthening phenomena occur in Korean to robustly preserve the contrastive length difference between C and CC. Second, this study examines the vowel shortening, known as Closed-Syllable Vowel Shortening, before a long tense stop or before the consonant sequence. Experiment 3 suggests that it be interpreted as temporal adjustment to make the interval from the onset of a vowel to the onset of the following vowel of near-equal length. Conclusively, we suggest that Korean speech be planned and controlled with two specific intervals. One is the duration of contrastive consonant intervals between vowels, and the other is the duration from the onset of a vowel to the onset of the following vowel.

• 말소리와 음성과학
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• 제6권3호
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• pp.81-89
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• 2014

Korean English learners tend to have difficulty perceiving and producing English vowels. The purpose of this study is to examine a link between perceived and produced vowel spaces of Korean learners of English. Sixteen Korean male and female participants perceived two sets of English synthetic vowels on a computer monitor and rated their naturalness. The same participants produced English vowels in a carrier sentence with high and low pitch variation in a clear speaking mode. The author compared the perceived and produced vowel spaces in terms of the pitch and gender variables. Results showed that the perceived vowel spaces were not significantly different in either variables. Korean learners perceived the vowels similarly. They did not differentiate the tense-lax vowel pairs nor the low vowels. Secondly, the produced vowel spaces of the male and female groups showed a 25% difference which may have come from their physiological differences in the vocal tract length. Thirdly, the comparison of the perceived and produced vowel spaces revealed that although the vowel space patterns of the Korean male and female learners appeared similar, which may lead to a relative link between perception and production, statistical differences existed in some vowels because of the acoustical properties of the synthetic vowels, which may lead to an independent link. The author concluded that any comparison between the perceived and produced vowel space of nonnative speakers should be made cautiously. Further studies would be desirable to examine how Koreans would perceive different sets of synthetic vowels.

• 말소리와 음성과학
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• 제14권2호
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• pp.11-17
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• 2022

English vowels play an important role in verbal communication. However, Korean students tend to experience difficulty pronouncing a certain set of vowels despite extensive education in English. The aim of this study is to apply speech recognition software to evaluate Korean students' pronunciation of English vowels in minimal pair words and then to examine acoustic characteristics of the pairs in order to check their pronunciation problems. Thirty female Korean college students participated in the recording. Speech recognition rates were obtained to examine which English vowels were correctly pronounced. To compare and verify the recognition results, such acoustic analyses as the first and second formant trajectories and durations were also collected using Praat. The results showed an overall recognition rate of 54.7%. Some students incorrectly switched the tense and lax counterparts and produced the same vowel sounds for qualitatively different English vowels. From the acoustic analyses of the vowel formant trajectories, some of these vowel pairs were almost overlapped or exhibited slight acoustic differences at the majority of the measurement points. On the other hand, statistical analyses on the first formant trajectories of the three vowel pairs revealed significant differences throughout the measurement points, a finding that requires further investigation. Durational comparisons revealed a consistent pattern among the vowel pairs. The author concludes that speech recognition and analysis software can be useful to diagnose pronunciation problems of English-language learners.

• 말소리와 음성과학
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• 제9권2호
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• pp.1-7
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• 2017

The purpose of this study is to investigate the relations between phonetic differences among Korean learners' production of English front vowels, pronunciation intelligibility and speaking proficiency test score. To do so, thirty Korean university students were asked (1) to read English text book paragraphs and (2) describe a picture. Two English native raters and one Korean rater evaluated Korean subjects' English pronunciation intelligibility and speaking. In addition, subjects' English vowel productions were acoustically analyzed(F0, F1, F2, vowel duration, intensity). The results of the study show that the vowel quality and pitch of the unstressed vowels and lax vowel are related to the pronunciation intelligibility. In addition, the scores of pronunciation intelligibility and speaking are highly related.

• 말소리와 음성과학
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• 제4권3호
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• pp.85-92
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• 2012

It is a well-known phenomenon that vowel duration in English is generally longer before a voiced stop than a voiceless one. Past research has postulated that the closure duration of the voiceless stop is generally longer than that of the voiced stop and that the duration of a preceding vowel is determined complementarily by the closure duration of the stop. To shed further light on the phenomenon, this study examined fourteen native speakers of American English who read the monosyllabic words [bVC] (V = [i, ɪ, eɪ, ɛ, æ, ʌ, ɑ], C = [t, d]). First, we found that mean vowel duration was 38 ms longer before the voiced stop than the voiceless (mean duration ratio = 1.24). Second, mean closure duration of the voiced stop was only shorter by 5 ms compared to the voiceless stop (mean duration ratio = 0.97). Therefore, for our subjects, vowel duration was not determined complementarily by the closure duration of the following stop. Third, vowels with longer inherent durations (viz., tense, diphthong, and low vowels) tended to show larger duration ratios in the voiced and voiceless contexts than the vowels with shorter durations (viz., lax vowels). This indicates that the lengthening of inherently shorter vowels before a voiced stop is limited in order to avoid overlapping with longer vowels in the duration range. Fourth, there was no significant gender difference in vowel duration ratios in the contexts of voiced and voiceless stops. Finally, considerable individual differences were found in the vowel and consonant duration ratios.