• Speech Sciences
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• v.7 no.1
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• pp.187-201
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• 2000

This study was done to investigate the English vowels in relation to the foreign accent. In this study, I also tried to find out the foreign accent of the English diphthong /o/ and front low vowel /${\ae}$/ when Koreans speak English. The reason why I chose these vowels is that these vowels, /o/ and /${\ae}$/, are difficult for Koreans to discern and pronounce. Koreans show a foreign accent in their pronunciation. In order to find out the reason for a Korean foreign accent, experiments were carried out with the help of acoustic instruments. According to the results of the experiment, Koreans showed a foreign accent in their English pronunciation of vowels in relation to their utterance positions. Americans showed a final lengthening effect but Koreans showed a final shortening effect. This means that Koreans showed a foreign accent in the final stressed syllable of a sentence. In addition to this, the duration of two English vowels, /o/ and /${\ae}$/, showed considerably different features between Koreans and Americans. In fact, in the pronunciation of the diphthong /o/, the tongue moves from one position to another. The two articulations of a diphthong can be described as the nucleus plus a glide. However, most Koreans have no idea of this phenomenon and pronounce the diphthongs like two separate monophthongs. This causes a great difference in the lengths of English diphthong /o/ between Koreans and Americans.

• The Journal of the Korea Contents Association
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• v.5 no.2
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• pp.251-256
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• 2005

When English monosyllabic words are adapted to the Korean language, the loanwords tend to carry extra syllables. The purpose of this paper is to find the syllable augmentation conditions in loanword adaptation and further to provide an algorithm to predict the syllable numbers of English monosylabic loanwords. Three syllable augmentation conditions are found as follows: 1) the existence of diphthong, 2) the existence of consonant clusters, and 3) the quality of the final consonant (and the preceding vowel). Based on these three conditions, an algorithm to predict the syllable number of English monosyllabic loanwords are proposed as three rules applied iteratively with ordering. In addition, the applications of the algorithm to data are given.

• Speech Sciences
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• v.8 no.3
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• pp.7-14
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• 2001

This study was done to find out the difference in vowel length between the English language produced by American soldiers 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 KATUSA soldiers, when compared with American soldiers, showed a foreign accent when they produced English diphthongs. The reason I wanted to deal with English diphthongs is that most Koreans have difficulty in pronouncing them since they do not understand the concept of diphthongs. Therefore I selected five English diphthongs, /aI/, cI/, /au/, /eI/, /ou,/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. I investigated the difference of the English diphthong length between American and KATUSA soldiers using information gathered from experimental results.

• Speech Sciences
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• v.9 no.4
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• pp.143-148
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• 2002

This study examined the foreign accent of Korean speakers of English concerning vowel length and utterance position. It then attempts to explain the foreign accent of Koreans when they speak English. The method was to measure the sentence-initial and sentence-final vowels as spoken by Koreans. I chose these two positions, sentence-initial and sentence-final, in order to know if Korean speakers of English, compared with native English speakers, show a difference in sentence stress. I chose English diphthongs, because most Koreans have difficulty pronouncing these sounds. I found that Korean speakers of English as a second language do not know English sentence stress patterns and show a foreign accent, especially when using diphthongs.

• 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.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.99-102
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• 2000

In the case of making large vocabulary speech recognition system, it is better to use the segment than the syllable or the word as the recognition unit. In this paper, we study on the basis of making biphone for Korean speech recognition. For experiments, we use the speech toolkit of OGI in U.S.A. The result shows that the recognition rate of the case in which the diphthong is established as a single unit is superior to that of the case in which the diphthong Is established as two units, i.e. a glide plus a vowel. And also, the recognition rate of the case in which the biphone is used as the recognition unit is better than that of the case in which the mono-phoneme is used.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.45-48
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• 2000

In the case of making large vocabulary speech recognition system, it is better to use the segment than the syllable or the word as the recognition unit. In this paper, we study on the basis of making mono-phone for Korean speech recognition. For experiments, we use the speech toolkit of OGI in U.S.A. The result shows that the recognition rate of :he case in which the diphthong is established as a single unit is superior to that of the case in which the diphthong is established as two units, i.e. a glide plus a vowel. And also, the recognition rate by the number of consonants is a little different.

• Speech Sciences
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• v.9 no.1
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• pp.77-88
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• 2002

Acoustical correlates of stress can be classified as duration, intensity and fundamental frequency. This study examined the acoustical differences in the first two syllables of stressed English words produced by ten American and Korean speakers. The Korean subjects scored very high on the TOEFL. They read at a normal speed a fable from which the acoustical parameters of eight words were analyzed. In order to make the data comparison meaningful, each parameter was collected at 100 dynamic time points proportional to the total duration of the two syllables. Then the ratio of the parameter sum of the first rime to that of the second rime was calculated to determine the relative prominence of the syllables. Results showed that the durations of the first two syllables were almost comparable between the Americans and Koreans. However, statistically significant differences showed up in the diphthong pronunciations and in the words with the second syllable stressed. Also, remarkably high r-squared values were found between pairs of the three acoustical parameters, which suggests that either one or a combination of two or more parameters may account for the prominence of a syllable within a word.

• MALSORI
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• no.46
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• pp.87-102
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• 2003

In this paper, we present an English pronunciation correction system for Korean speakers and show some of experimental results on it. The aim of the system is to detect mispronounced phonemes in spoken words and to give appropriate correction comments to users. There are several English pronunciation correction systems adopting speech recognition technology, however, most of them use conventional speech recognition engines. From this reason, they could not give phoneme based correction comments to users. In our system, we build two kinds of phoneme models: standard native speaker models and Korean's error models. We also design recognition network based on phonemes to detect Koreans' common mispronunciations. We get 90% detection rate in insertion/deletion/replacement of phonemes, but we cannot get high detection rate in diphthong split and accents.

• Phonetics and Speech Sciences
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• v.2 no.2
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• pp.43-50
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• 2010

English vowels can be divided into monophthongs and diphthongs depending on the number of vocal tract shapes. Diphthongs are usually produced with more than one shape. This study attempts to collect acoustical data of English diphthongs published by Hillenbrand et al.(1995) online and to examine acoustic features of the diphthongs for phoneticians and English teachers. Sixty three American males and females were chosen after excluding those subjects with different target vowels or ambiguous formant tracks. The author used Praat to obtain the acoustical data systematically at eleven equidistant timepoints over the diphthongal segment. Obvious errors were corrected based on the spectrographic display of each diphthong. Results show that the formant trajectories of the diphthongs produced by the American males and females appeared quite similar. When the female formant values were uniformly normalized to those of the males, almost a perfect collapse occurred. Secondly, the diphthongal movements on the vowel space appeared not linear due to the coarticulatory gesture for the following consonant. Thirdly, the average duration of the diphthongs produced by the females was 1.156 times longer than that of the males while the pitch ratio between the two groups turned out to be 1.746 with a similar contour over measurement points. The author concludes that English diphthongs produced by various groups can be compared systematically when the acoustical values are obtained at proportional timepoints. Further studies will be desirable on the comparison of English diphthongs produced by native and nonnative speakers.