• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.65-72
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• 2009

Formant values are the most important acoustic correlates of English vowels. Classical studies on English vowels reported the first three formant values measured at a single timepoint on a sustained vowel segment. However, many recent studies revealed that partial onset or offset segments with information of dynamic spectral changes may contribute to the exact identification of English vowels with an accuracy almost comparable to that by the whole vowel segment or word. The purpose of this study was to examine formant trajectories of nine English vowels collected by Hillenbrand et al.(1995). Acoustic analysis was systematically made by a Praat script at six equidistant timepoints over the vowel segment. Results showed that the first formant trajectories played an important role in distinguishing each vowel within the front- or back-vowel groups. The second formant trajectories of the back vowels varied more drastically than those of the front vowels. The third formant value was similar except the high vowel /i/. From the vowel space on F1 by F2 axes, the formant trajectories of each vowel clearly showed a transition toward the locus of the following consonant /d/. Other acoustic data revealed that there were some vowel inherent duration or pitch values. From this study we can conclude that the dynamic spectral changes are very important in specifying acoustic characteristics of the English vowels. Further studies on vowels and diphthongs in different contexts are desirable.

• Phonetics and Speech Sciences
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• v.3 no.2
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• pp.53-61
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• 2011

The present work is a follow-up study to that of Han, Choi, Lim and Lee (2011), where an asymmetry in the source segments eliciting the interlanguage speech intelligibility benefit (ISIB) was found such that the vowels which did not match any vowel of the Korean language were likely to elicit more ISIB than matched vowels. In order to identify the source of the stronger ISIB in non-matched vowels, acoustic analyses of the stimuli were performed. Two pairs of English front vowels [i] vs. [I], and $[{\varepsilon}]$ vs. $[{\ae}]$ were recorded by English native talkers and two groups of Korean learners according to their English proficiency, and then their vowel duration and the frequencies of the first two formants (F1, F2) were measured. The results demonstrated that the non-matched vowels such as [I], and $[{\ae}]$ produced by Korean talkers seemed to show more deviated acoustic characteristics from those of the natives, with longer duration and with closer formant values to the matched vowels, [i] and $[{\varepsilon}]$, than those of the English natives. Combining the results of acoustic measurements in the present study and those of word identification in Han et al. (2011), we suggest that relatively better performance in word identification by Korean talkers/listeners than the native English talkers/listeners is associated with the shared interlanguage of Korean talkers and listeners.

• Speech Sciences
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• v.5 no.2
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• pp.131-138
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• 1999

This study was done to investigate the English front vowels /e/ and /${\ae}$/. These vowels are difficult for Koreans to discern and pronounce. So they show a foreign accent in pronouncing them. In order to find out the reason for Koreans' foreign accent, experiments are carried out with the help of acoustic instruments. The results of the experiment show that there is a considerable difference, especially in vowel length, between the way Korean and Americans pronounce the two English vowels, /e/ and /${\ae}$/. When Americans pronounced English front vowel /e/ and /${\ae}$/ there was a big difference in vowel length between the two vowels. But for Koreans there was only a little difference between two vowels and as a result Koreans showed a foreign accent when they spoke these two English front vowels. Therefore we need to consider the difference of vowel lengths between /e/ and /${\ae}$/ in teaching English pronunciation.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.13 no.1
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• pp.45-51
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• 2002

The purpose of this study is to examine the effects of vowel type on the nasalance score. Twenty one male adults without VPI produced 5 types of vowels (/a/, /e/, /i/, /o/, /u/) in two conditions-normal and simulated VPI condition. Nasalance scores were measured for each vowel. These data were compared between conditions and among vowel types. The results were as follow : For all vowels, nasalance scores were significantly higher in simulated VPI condition than in normal condition. The two conditions yielded different patterns in terms of the degree of nasalance across the 5 vowels. In normal condition, nasalance scores were higher in front vowels than in medial or back vowels. But in simulated VPI condition, nasalance scores were higher in high vowels than in mid or low vowels.

• 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.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.

• Speech Sciences
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• v.12 no.2
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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/.

• MALSORI
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• no.35_36
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• pp.121-129
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• 1998

In this paper, articulatory simulator 'Artsim' is used as a tool for the experiments to examine the articulatory characteristics of 6 different vowels. Each vowels are defined by some articulatory points from their vocal tract area functions and shapes of tongues. Each points are varied systematically to synthesize vowels and the synthesized sound is evaluated by human listners. Finally distributions of each vowels within vowel space is obtained. From the experimental results it is verified that our articulatory simulator can be used effectively to investigate the articulatory characteristics of speech.

• MALSORI
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• no.62
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• pp.1-17
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• 2007

The purpose of this study was to investigate and quantitatively describe the acoustic characteristics of current Korean monophthongs. Recordings were made of 33 men and 27 women producing the vowels /i, e, ${\epsilon}$, a, ${\partial}$, o, u, i/ in a carrier phrase "This character is ___." A listening test was conducted in which 19 participants judged each vowel. F1, F2, and F3 were measured from the vowels judged as intended vowels by more than 17 people from the listening test. Analysis of formant data shows some interesting results including the undeniable confirmation of the 7-vowel system in modern Korean. It turns out that quite different sounding Korean vowels and English vowels happen to have very similar formant measurements. Also the difference between "citation-form reading" vs. "natural utterance reading" is discussed.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.22 no.6
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• pp.1160-1169
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• 1997

This paper presents an algorithm to separate vowels from consonants in Korean characters captured in noisy environment andto recognize them. The algorithm has been originally developed for recognition of the usage code (which is represented by a single Korean character) in the license plates of Korean vehicles. It, however, could be easily adopted to other applications with minor changes, in which character recognition is needed and the environment is noisy. The key ideas of the algorithm are to localize the vowels utilizing Hough transformation and to separate the vowels from consonants utilizing mathematical morphology. We observed that the presented algorithm effectively separates vowels even if the vowels and consonants are joined together after thresholding. We also observed that our algorithm outperforms some conventional algorithms especially when the input images are noisy. The details of the comparison study are presented in the paper.