• Speech Sciences
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• v.14 no.4
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• pp.81-98
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• 2007

This study aims to investigate whether shortened vowel duration conditioned by a following voiceless stop induces phonetic reduction of vowel space in English, and whether the reduction appears more in the height dimension than in the backness dimension (Lindblom, 1963; Flemming, 2005). Fifteen native speakers of American English read minimal pairs containing ten American English vowels in [bVd] and [bVt] syllables in a carrier phrase. All the subjects produced shorter vowels in the voiceless than in the voiced context. However, a reduction in vowel space and a raising of low vowels due to the shortened vowel duration were generally not found. To the contrary, the speakers tended to exhibit even more lowering of low vowels in the voiceless context, and vowel space was more commonly compressed in the backness dimension than in the height dimension. Many speakers, in particular, demonstrated fronting of the high back vowel [u] in the voiceless context. It was interpreted that due to a relatively large number of English vowels in the narrower low vowel space, the raising of low vowels may give rise to confusion in vowel contrasts, and therefore the degree of phonetic vowel reduction is restricted in that region. On the other hand, the high vowel region, being relatively spacious in English, allows a certain degree of phonetic vowel reduction in the F2 dimension. It is possible that heavy requirements for maintaining vowel contrasts may cause speakers to overachieve vowel target values, especially when faced with vowels which are difficult to distinguish due to shortened vowel duration, leading to an over-lowering of the low vowels.

• Speech Sciences
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• v.8 no.4
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• pp.215-220
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• 2001

This study was done to find out the difference in vowel length between English produced by Americans and KATUSA soldiers. Though English pronunciation by Koreans shows different features in many ways, I focused on English vowel length of KATUSA soldiers. I wanted to know if English low vowels show a foreign accent by comparing vowel lengths in English produced by Americans and KATUSA soldiers. The reason I wanted to deal with English low vowels is that most Koreans have difficulty in pronouncing them. Therefore I selected three English low vowels, /$\{\ae}$, /c/, and/$\alpha$/, as the experimental object, and I tried to find out the foreign accent of them. In this study, I also tried to find out the vowel lengths in relation to their utterance positions and see the foreign accent of English low vowels. I investigated the difference of the English low vowels lengths between Americans and KATUSA soldiers using information gathered from experimental results.

• Phonetics and Speech Sciences
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• v.8 no.3
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• pp.111-116
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• 2016

The Nasometer is most commonly used to assess the presence and degree of resonance problems in clinical settings and it provides nasalance scores to identify the acoustic correlates of nasality. Nasalance scores are influenced by factors related to speakers and speech stimuli. This study aims to examine the effect of vowel context and length of stimuli and age on nasalance scores. The participants were 20 adults and 45 children ranging in age from 3 to 5 years. The stimuli consisted of 12 sentences containing no nasal consonants. The stimuli in the three vowel contexts (low, high, and mixed) consisted of 4, 8, 16, and 31-syllable long sentences. Speakers were asked to repeat each stimulus after examiner. The results indicated significant effects of vowel contexts and stimulus length on nasalance scores. The nasalance scores for the high vowel contexts were significantly higher than those for the mixed and low vowel contexts. The nasalance scores for the mixed vowel contexts were significantly higher than those for the low vowel contexts. Speakers had higher nasalance scores for 4-syllable long sentences and 31-syllable long sentences than for 16-syllable long sentences. The effect of age on nasalance scores was not significant. The results of the study suggest that the vowel context and length of speech stimuli should be carefully considered when interpreting the nasalance scores.

• Proceedings of the KSPS conference
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• 2000.07a
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• pp.199-199
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• 2000

Korean stops are 3 system: aspirated, fortis, lenis, whereas English stops are 2 system: voiced, voiceless. Because in Korean, lenis stop is realized by slight aspirated voiceless stop, it is likely to produce English word initial voiced stop as voiceless stop. We divide subjects into three group-native, experienced, unexperienced- and investigate differences between group. VOT of experienced group IS same as native group, but VOT of unexperienced group is longer than native group. VOt of unexperienced group is 1.8 times than native group. We survey whether the height of following vowel influences VOT of initial stop. As a result, for all group, VOT followed by low vowel is shorter than VOT followed by high vowel. But this tendency is more salient in unexperienced group. For high vowel, VOT of unexperienced group is 2.05 times than native group, whereas for low vowel, it is just 1.55 times. The unexperienced pronounce well English word initial voiced stop followed by low vowel than high vowel. Samples are divided into two group according to type of coda consonant- nasal and voiceless stop. But average of VOT is similar and there is no significant difference between two groups. There is no influence by type of coda consonant. The average of phrases is compared to the average of isolated words. In the case of natives and experienced, there is no significant differences between phrases and words, but in the case of unexperienced, VOT of phrases becomes shorter than words. But VOT of unexperienced is still longer than native group.

• Phonetics and Speech Sciences
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• v.7 no.1
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• pp.79-86
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• 2015

This study explored the vowel effect on acoustic perturbation measures in voice quality analysis. For this study, the perturbation parameters (%jitter, %shimmer) and noise parameter (SNR) were measured with 7 Korean vowels (/a/, /ɛ/, /i/, /o/, /u/, /ɯ/, /ʌ/) using CSpeech with 50 Korean normal young adults (24 males and 26 females). A significant vowel effect was found only in %shimmer and in particular, low-back /a/vowel was significantly different from other vowels in %shimmer. The least perturbation and noise were exhibited on high-back /ɯ/ and /o/ vowel, respectively. Based on tongue height, a significant higher %shimmer was demonstrated on low vowels than high vowels. In addition, back vowels in tongue advancement and rounded vowels in lip rounding showed significantly less perturbation and noise. The least variability of perturbation and noise within individuals was demonstrated on the vowel /i/ in three repeated measures. However, there was no significant difference among 3 token measures in single session among vowels tested except the vowel /o/. Consequently, the vowel /a/ commonly used in acoustic perturbation measures exhibited higher perturbation and noise whereas higher stability and less variability were demonstrated on the high-back vowel /u/. These results suggested that the Korean high-back vowel /u/ can be more appropriate and reliable for perturbation acoustic measures.

• Phonetics and Speech Sciences
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• v.6 no.3
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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.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.87-93
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• 2009

The purpose of this experimental study is to investigate and compare the vowel lengths of English diphthongs and low vowels among native-English-speaking Americans and Korean college exchange students. To do this eight words and sixteen sentences were uttered and recorded by nine subjects, five Korean subjects and four American subjects. Results showed that the vowel lengths of English low vowels between American subjects and Korean subjects were different, which may lead to foreign accent of Korean speakers. Comparing the average length of English low vowels of Korean subjects with those of American subjects, we can see that American subjects tend to pronounce the English low vowels longer than Korean subjects do. In the pronunciation of diphthongs /eI/ and /ou/, Korean subjects pronounced longer than American subjects did. However, in the pronunciation of diphthongs /au/, /aI/, and /ɔI/, American subjects pronounced longer than Korean subjects did.

• Journal of Digital Contents Society
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• v.13 no.3
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• pp.279-290
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• 2012

The purpose of this experimental study is to investigate and compare the vowel lengths of the English diphthongs, /eɪ/ and /aɪ/, and the front low vowel /æ/ among English-speaking natives with Korean college students using the Praat software program. To do this English sentences were uttered and recorded by twelve subjects, six Korean subjects and six English-speaking native subjects. All the subjects are female and their age ranges from 23 to 35. Acoustic features(duration) were measured from a sound spectrogram with the help of the Praat software program and analyzed through statistical analysis. Results showed that the vowel lengths of the English diphthongs and the front low vowel between native English speakers and Korean collegians were different. In the pronunciation of the diphthongs /eɪ/ and /aɪ/, Korean subjects pronounced longer than native subjects did, but the difference was not significant. However, in the pronunciation of the English front low vowel /æ/, native subjects pronounced significantly longer than Korean subjects did. From the data of the overall sum of words and vowels between the two subject groups, we were able to find out that the differences of lengths of both the three words and the two diphthongs /eɪ/ and /aɪ/ were not significant, but those of /æ/ were significant.

• Speech Sciences
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• v.10 no.3
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• pp.157-173
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• 2003

The purpose of this experimental study is to investigate and compare the. vowel lengths of English diphthongs and low vowels among native-English-speaking Americans with Korean college students from the Chungnam and Gyungnam provinces. Eight words and sixteen sentences were uttered five times by twenty five subjects from three groups; 1) Chungnam dialect speakers, 2) Gyungnam dialect speakers and 3) five native-English-speaking Americans. Acoustic features (duration) were measured from sound spectrograms made by the PC Quire. Results showed that the vowel lengths of English diphthongs and low vowels between native English speakers and Korean collegians of Chungnam and Gyungnam provinces were different. Comparing the average length of English diphthongs of Korean collegians with those of American natives, we can see that native English speakers tend to pronounce the English diphthongs shorter than Korean collegians do. However, native English speakers tend to pronounce the English low vowels longer than Korean collegians do. In this study we also tried to find out the differences of English diphthongs and low vowel lengths in relation to their utterance positions among American natives and Chungnam and Gyungnam dialect speakers. By the results of this experiment, we observed a lengthening effect in the three groups. However, in the pronunciation of American natives, a lengthening effect of English vowels was more clearly observed, especially in the pronunciation of English diphthongs.

• Speech Sciences
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• v.13 no.1
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• pp.7-27
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• 2006

This study explored the discrimination of synthesized English vowel pairs by twenty-seven American and Korean, male and female listeners. The average formant values of nine monophthongs produced by ten American English male speakers were employed to synthesize the vowels. Then, subjects were instructed explicitly to respond to AX discrimination tasks in which the standard vowel was followed by another one with the increment or decrement of the original formant values. The highest and lowest formant values of the same vowel quality were collected and compared to examine patterns of vowel discrimination. Results showed that the American and Korean groups discriminated the vowel pairs almost identically and their center formant frequency values of the high and low boundary fell almost exactly on those of the standards. In addition, the acceptable range of the same vowel quality was similar among the language and gender groups. The acceptable thresholds of each vowel formed oval to maintain perceptual contrast from adjacent vowels. The results suggested that nonnative speakers with high English proficiency could match native speakers' performance in discriminating vowel pairs with a shorter inter-stimulus interval. Pedagogical implications of those findings are discussed.