• Proceedings of the KSPS conference
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• 2005.11a
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• pp.91-95
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• 2005

The aim of this paper is to investigate the effects of postvocalic voicing(Contrasting voiceless fricative and affricate with voiced fricative and affricate) on vowel duration. In particular we focused on the durational differences between vowels followed by voiceless and voiced consonants across three groups of speakers: English speakers, English bilinguals and Korean learners of English. the result of experimental I showed that durations of vowels preceding voiced fricative and affricates as well as voiced stops are significantly longer than those preceding voiceless counterparts. Experiment Ⅱ indicated that as the subjects exposed themselves longer to English speaking society, their pronunciation was increasingly similar to those of English native speakers.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.29-37
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• 2009

This paper presents results from speech production experiments on English, Korean, and Hindi that compare variation in the acoustic expression of dissimilar phonological laryngeal contrast in stops conditioned by prosodic prominence. Target stops are analyzed from utterance-initial, -medial, and -final positions, with a variation in contrastive focal accent, from the speech data by six male American English speakers, five male Seoul Korean speakers, and five male Delhi Hindi speakers. The results show that prosodic prominence conditions enhanced distinctiveness between contrastive segments in the three languages. The manner in which prosodic prominence and prosodic phrase structure is marked at the level of segmental variation is, however, found to be language-specific to some extent. In addition, a correlation between the size of the phonological inventory and the corresponding acoustic variation was found but the linear correlation was not strongly supported with the findings in the present study.

• Speech Sciences
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• v.10 no.1
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• pp.27-39
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• 2003

This study attempts to verify the reliability of automatically generated segment labels as compared to those obtained by conventional labelling by hand. First of all, an autolabeller is constructed using the standard HMM speech recognition technique. For evaluation, we compare the automatically generated labels with manually annotated labels for the same speech data. The comparison is performed by calculating the temporal difference between an autolabel boundary and its corresponding hand label boundary. When the mismatched duration between two labels falls within 10 msec, we consider the autolabel as correct. The results suggest that overall 78% of autolabels are correctly obtained. It is found that the boundary of obstruents is better aligned than that of sonorants and vowels. In case of stop sound classes, strong stops in manner-of-articulation wise and velar stops in place-of-articulation wise show better performance in boundary alignment. The result suggests that more phone-specific consideration is necessary to improve autosegmentation performance.

• Phonetics and Speech Sciences
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• v.1 no.3
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• pp.39-48
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• 2009

Previous studies on the effects of speaking rate on voice onset time (VOT) of stops in English, French, Icelandic, and Thai indicate that speaking rate asymmetrically affects VOT values. That is, pre-voiced and long-lag stops vary due to the rate factor more than short-lag stops do. One suggested explanation for this asymmetry is that it is due to the necessity of maintaining phonetic contrasts among the stop categories. Since pre-voiced and long-lag stops represent the ends of the VOT scale, they encompass broad swathes of that range and consequently allow for large variations. On the other hand, the VOT variations of short-lag stops may result in overlap with the VOTs of long-lag stops. This study aimed to explore the effects of speaking rate on the VOTs of Korean stops and see whether Korean fortis and lenis stops are limited in the degrees of variation as a function of rates due to the existence of stops with larger VOT values, lenis and aspirated stops respectively. Conversely, aspirated stops were expected to show more variation since there are no other categories with longer VOTs. Fortis, lenis, and aspirated stops in /CVn/ words (C = bilabial or velar stop, V = /i/ or /a/) were examined in isolation, and at normal and fast rates in a carrier sentence. Speaking rates were controlled by alternating words or sentences on a computer screen at intervals of two seconds for the isolation- and normal-rate conditions and one second for the fast-rate condition. This study found that while the VOTs of fortis stops did not change significantly, those of lenis and aspirated stops showed considerable changes as a function of speaking rates. Also, overlap between lenis and aspirated stops occurred considerably at all speaking rates. These phenomena were interpreted to relate to the fact that VOT contrasts between lenis and aspirated stops in Korean are currently being collapsed. Large variations of lenis stops as a function of rates seem to occur due to a weak motivation to limit the degree of variations for the purpose of maintaining phonetic contrasts. The significant overlap between lenis and aspirated stops at all rates was interpreted to occur because the VOT merger between the two categories became considerably fixed. Also the percentage of correctly-classified VOTs by optimal-boundary values between lenis and aspirated stops turned out to be lower than in previously-studied languages. This was interpreted to be further evidence that VOTs are losing their role in contrasting the two stop categories in Korean.

• Phonetics and Speech Sciences
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• v.6 no.1
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• pp.47-58
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• 2014

The purpose of this paper is to find out how Korean speakers' speech production in English word boundaries differs from English speakers' and to account for what bring about such differences. Seeing two consecutive words as one single cluster, the English speakers generally pronounce them naturally by linking a word-final consonant of the first word with a word-initial vowel of the second word, while this is not the case with most of the Korean speakers; they read the two consecutive words individually. In consequence, phonological processes such as resyllabification and aspiration can be found in the English speakers' word-boundary production, while glottalization, and unreleased stops are rather common phonological process seen in the Korean speakers' word-boundary production. This may be accounted for by Korean speakers' L1 interference, depending on English proficiency.

• The Journal of the Korea Contents Association
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• v.10 no.5
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• pp.460-466
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• 2010

It is well-known that Korean EFL learners have difficulties in producing English fricatives which are not in the inventory of Korean and consequently tend to replace English fricatives with stops. The purpose of this paper is to investigate whether Korean students also have difficulties perceiving English anterior coronal consonants including fricatives. To this end, forty Korean college students participated in an identification test which consisted of 24 nonce words with English anterior coronal consonants in 4 different prosodic locations (CV, VC, VCVV,VVCV). It was shown that the mean accuracy rates were higher in strong position like CV and VCVV than in weak position like VC and VVCV, providing confusion matrices for each target consonant. It was also found that Korean participants had a great difficulty identifying English[$\theta$] and [$\eth$], which are novel in Korean. Importantly, the confusion patterns found in the perception test tended not to be identical with those found in the previous production studies in that both stops and fricatives were misperceived as fricatives while fricatives were misproduced as stops. Further, perceptual devoicing and intervocalic voicing were attested inVC and intervocalic position, respectively. Based on the findings of this study, pedagogical implications were drawn.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.51-58
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• 2012

The purpose of this study is to measure the impact of Korean speakers' English stop pronunciation on their general pronunciation proficiency. For these purposes, 20 Korean speakers read English sentences and their pronunciations were rated by native English speakers. The Korean speakers' VOT values of English stops in sentences were then measured and the relation between the VOT values and native speakers' pronunciation rating was compared. Here, the relation between (1) the proficiency score of each speaker and VOT values; and (2) the proficiency score of each sentence and VOT values were analyzed. The results show that there is a relation between the proficiency score of each sentence and VOT values of /t, b, d, g/; and there is a relation between VOT values of /t, b, d, g/ and proficiency scores of each speaker while these is a weak relation between VOT values of /p, k/ and proficiency scores of each speaker.

• Speech Sciences
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• v.7 no.1
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• pp.203-216
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• 2000

The purpose of this study is to revisit the property of the Korean plain stops in intervocalic position. More specifically, focusing on a word-internal, intervocalic position, this study investigates 1) how often speakers pronounce intervocalic. stops as fully voiced, 2) in what amount each speaker voice the plain stops during the stop closure, 3) whether the preceding or the following vowel influences the voicing of target consonants, and 4) the fundamental frequency pattern at the vowel onset after the target consonant shows any consistent pattern, regardless of whether voicing is present during the closure. The results of this study give strong support for the phonetic account of the voicing distinction in Korean. (Jun 1995, 1996).

• Speech Sciences
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• v.7 no.3
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• pp.21-33
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• 2000

There are two hypotheses with reference to voicing in Korean intervocalic lax stops /p, t, k/ and affricate /c/: (1) the phonologically voiceless lax stops /p, t, k/ and affricate /c/ are realised as voiced allophones in the intervocalic position; (2) the shorter the lax consonant, the higher the percentage of voicing. But the literature reveals that there are views rejecting or doubting them. To clarify these, an experiment was carried out, using a Sun Sparcstation, twelve native speakers of Korean and speech materials embedded in a sentence frame. The results showed that the extent of voicing in lax stops and affricate was too inconsistent to support the full voicing hypothesis, and shorter duration (faster speech) did not necessarily cause a higher percentage of voicing.

• Speech Sciences
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• v.14 no.3
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• pp.7-19
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• 2007

The present study investigated some phonetic attributes which distinguish two Korean stop types $^-aspirated$ and $lax^-$ in a prosodic position which has previously received little attention, namely medial in an accentual phrase. The intonational pattern across syllables which are initial in an accentual phrase (Jun, 1993) is said to depend on the type of stop (aspirated or lax), while that of syllables which are medial in an accentual phrase are not. In Experiment 1, nine native Korean speakers read sentences with a controlled prosodic pattern in which aspirated or lax stops occurred in accentual phrase-medial position. Acoustic analysis revealed significant differences between aspirated and lax stops in closure duration, voice-onset time, and fundamental frequency (F0) values for post-stop vowels. The results indicate that a wider range of acoustic cues distinguish aspirated and lax Korean stops than previously demonstrated. Phonetic and phonological models of consonant-tone interactions for Korean will need to be revised to account for these results.