• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.37-44
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• 2021

Preliminary findings are reported from five experiments testing the perceived naturalness of word tokens whose vowel durations are altered. The stimuli were minimal pairs of English words ending in a voiced/voiceless plosive. Results show an asymmetric effect of shortening and lengthening of the vowel on the perceived naturalness of the word. Incremental shortening of vowel duration initially shows a stable degree of perceived naturalness but rapidly deteriorates beyond a certain point. On the contrary, only a small degree of lengthening of the vowel made the perceived naturalness of the word quickly decay, but there was a floor effect such that the perceived degree of naturalness does not lower beyond a certain level. Further, the tokens with the original vowel duration were not always scored higher than the stimuli with a small degree of shortening. Future studies should address the issue of speaking rate and the ratio between the vowel and the stop closure duration to better understand the phenomenon. The issue investigated here has implications on the role of prototypical exemplars in the perception of phonotactic naturalness.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.99-107
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• 2013

The purpose of this study is to examine the relative distances among English front vowels in a message produced by 47 Korean and American speakers in order to better instruct pronunciation skills of English vowels for Korean English learners. A Praat script was developed to collect the first and second formant values(F1 and F2) of eight words in each sound file which was recorded from an internet speech archive. Then, the Euclidean distances were measured between the three vowel pairs: [i-ɛ], [i-ɪ], and [ɛ-æ]. The first vowel pair [i-ɛ] was set as the reference from which the relative distances of the other two vowel pairs were measured in percent in order to compare the vowel sounds among speakers of different vocal tract lengths. Results show that F1 values of the front vowels produced by the Korean and American speakers increased from the high front vowel to the low front vowel wih differences among the groups. The Korean speakers generally produced the front vowels with smaller jaw openings than the American speakers did. Secondly, the relative distance of the high front vowel pair [i-ɪ] showed a significant difference between the Korean and American speakers while that of the low front vowel pair [ɛ-æ] showed a non-significant difference. Finally, the Korean speakers in the higher proficiency level produced front vowels with higher F1 values than those in the lower proficiency level. The author concluded that Korean speakers should produce the front high vowels distinctively by securing sufficient relative distance of the formant values. Further studies would be desirable to examine how strong the Korean speakers' English proficiency correlate with the relative distance of target words of comparable productions.

• Speech Sciences
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• v.12 no.1
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• pp.75-87
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• 2005

In this study I investigate how native Korean listeners perceive English vowels /i/, /I/, and /$\epsilon$/. I extend Flege et al's (1997) study with synthesized /i/-/I/ and /I/-/$\epsilon$/ continua, and apply the results to Flege's (1995) Speech Learning Model (SLM). The statistical results show that native speakers of English rely more on spectral steps than on vowel duration when they identify the /i/-/I/ continuum, whereas native speakers of Korean rely more on vowel duration than on spectral steps when they identify the same continuum. In the case of the /I/-/$\epsilon$/ continuum, both groups rely on spectral steps when they identify the /$\epsilon$/, which supports the SLM; Koreans identified the /$\epsilon$/ categorically since Korean has the equivalent vowel. However, there was not statistical difference between Korean subjects with more English experience (KE) and those with less English experience in the identification of both continua. This contradicts the SLM, which posits that experienced L2 learners are better than inexperienced L2 learners in perception of L2 sounds. The exact nature of this should be further investigated in the SLM.

• Phonetics and Speech Sciences
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• v.5 no.2
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• pp.53-58
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• 2013

The purpose of this study is to compare the first two vowel formants of the stressed and unstressed English vowels produced by ten young males (in their twenties and thirties) and ten old males (in their forties or fifties) from the Buckeye Corpus of Conversational Speech. The results indicate that the stressed and unstressed vowels, /i/ and $/{\ae}/$ in particular, from the two groups are different in their formant frequencies. In addition, the vowel space of the unstressed vowels is somewhat smaller than that of the stressed vowels. Specifically, the range of the second formant of the unstressed vowels and that of the first formant of the unstressed front vowels were compressed. The findings from this study can be applied to the pronunciation training for the Korean learners of English vowels. We propose that teachers of English pay attention to the stress patterns of English vowels as well as their formant frequencies.

• 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.

• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.79-88
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• 2015

English vowels are difficult to teach and learn because both teachers and learners cannot show or see shapes of vocal tract inside their own mouth cavities. The aim of this study is to examine what kind of changes occur in production and perception of English vowels by college students before and after lessons in order to provide fundamental materials for teaching students English vowels. Fifteen volunteer female students attending an English phonetics course participated in the lessons for one and half a month period. Formant values of vowels produced and perceived before and after the lessons were obtained using Flying Popcorn and Praat. Results showed that a produced vowel space after the lessons was greater than that before the lessons with no significant difference. Distances between some adjacent corner vowels were too close to be distinguished. Secondly, perceived vowels before and after the lessons were almost the same. Here again, some adjacent vowels were closely spaced. Thirdly, three groups which were divided by the length of the distance between the vowel /i-${\ae}$/ showed similar patterns in their perception and production. Generally the vowel space expanded from [u] to [${\ae}$]. The author concluded that there was no drastic improvement of vowel perception and production within a short period of time. Further studies would be desirable to examine how successful any long-term English vowel lessons would be and which methods should be taken to evaluate students' achievements proposed here.

• 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.10 no.4
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• pp.11-17
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• 2018

This study reports on a production experiment designed to investigate how Korean speaking learners of English produce English forms ending in stops. In a repetition experiment, Korean participants listened to English nonce words ending in a stop and repeated what they heard. English speakers were recruited for the same task as a control group. The experimental result indicated that the transcriptions of the Korean productions by English native speakers showed vowel insertion in only 3% of productions although the pronunciation of English final stops showed that noise intervals after the closure of final stops were significantly longer for Korean speakers than for English speakers. This finding is inconsistent with the loanword data where 49% of words showed vowel insertion. It is also not compatible with the perceptual similarity approach, which predicts that because Korean speakers accurately perceive an English final stop as a final consonant, they will insert a vowel to make the English sound more similar to the Korean sound.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.51-58
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• 2010

English vowels play an important role in the daily communication between Korean students and international visitors. However, many Korean students still have difficulty producing them distinctively. Vowels vary according to shapes of oral and pharyngeal cavities, which are mainly determined by the degree of jaw opening and tongue position. Yang (2008a) proposed a simplified chart of English and Korean vowels for an educational purpose. He also suggested to use wooden chopsticks to secure distinguishable jaw openings. The purpose of this study is to tap whether wooden chopsticks can be applicable to a method for correcting English vowel pronunciation. Twelve male and female students participated in the recordings of eight /hVd/ words followed by additional recordings with wooden chopsticks between upper and lower teeth. The first and second formant trajectories of both natural and controlled vowel productions were obtained and compared at six equidistant measurement points using Praat. Results showed that the formant values of natural vowel productions were comparable to those of controlled productions. Vowels with similar formant trajectories of male students were separated with the aid of chopsticks. The width of each chopstick could be controlled similarly in the experiment. The author concludes that wooden chopsticks can be useful to correct vowel pronunciation. Further studies are desirable for native speakers to make perceptual evaluations of controlled vowel productions by nonnative speakers.

• MALSORI
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• no.44
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• pp.15-32
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• 2002

The purpose of this study is to investigate the production of English vowels by native speakers of Korean. In the production test, two English speakers and four native Korean speakers served as subjects. The four native Korean speakers were divided into two groups, experienced and inexperienced. Native English speakers generally showed significant differences both in vowel duration and in F1 & F2 values between members of vowel pairs which are of special interest of this study: /i/l vs. /I/, /$\varepsilon$/ vs. /${\ae}$/, and /u/ vs. /$\mho$/. The overall results showed that the experienced group produced more accurate results in vowel duration, F1, and F2 values.