• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.19-25
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• 2021

It has been widely recognized that there are two varieties of lateral liquid /l/, which are light /l/ (a non-velarized allophone) and dark /l/ (a velarized allophone). However, this categorical view has been challenged in recent studies, both on articulatory and acoustic aspects. The purpose of this study is to investigate whether to consider /l/ velarization as a continuum in American English and provide supporting data. A spontaneous American English speech database called the Buckeye Speech Corpus was used for the material. The formant frequencies of /l/ in each syllable position were measured and analyzed statistically. The formant frequencies of /l/ in each syllable position, especially F2 values, were significantly different from each other. The results showed that there were other significantly different varieties of /l/ in American English, which support the continuum view on /l/ velarization. Regarding the effect of the adjacent vowel, the backness of the adjacent vowels was shown to affect the degree of /l/ velarization, regardless of the syllable position of the lateral liquid. This result will help provide a solid ground for the continuum view.

• Phonetics and Speech Sciences
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• v.15 no.1
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• pp.25-34
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• 2023

This study examined the utility of the acoustic features of vowels as cues for the place of articulation of Korean nasal consonants. In the acoustic analysis, spectral and temporal parameters were measured at the 25%, 50%, and 75% time points in the vowels neighboring nasal consonants in samples extracted from a spontaneous Korean speech corpus. Using these measurements, linear discriminant analyses were performed and classification accuracies for the nasal place of articulation were estimated. The analyses were applied separately for vowels following and preceding a nasal consonant to compare the effects of progressive and regressive coarticulation in terms of place of articulation. The classification accuracies ranged between approximately 50% and 60%, implying that acoustic measurements of vowel intervals alone are not sufficient to predict or classify the place of articulation of adjacent nasal consonants. However, given that these results were obtained for measurements at the temporal midpoint of vowels, where they are expected to be the least influenced by coarticulation, the present results also suggest the potential of utilizing acoustic measurements of vowels to improve the recognition accuracy of nasal place. Moreover, the classification accuracy for nasal place was higher for vowels preceding the nasal sounds, suggesting the possibility of higher anticipatory coarticulation reflecting the nasal place.

• Phonetics and Speech Sciences
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• v.12 no.3
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• pp.85-94
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• 2020

Vowel articulation in subjects related to speech disorders seems to be difficult. A chant method that properly reflects the characteristics of language could be used as an effective way of addressing the difficulties. The purpose of this study was to find out whether the chant method is effective as a means of enhancing vowel articulation. The subjects of this study were 60 normal adults (30 males and 30 females) in their 20s and 30s whose native language is Korean. Eight utterance conditions including chanting and reading conditions were recorded and their acoustic data were analyzed. The results of the analysis of the acoustic variables related to the formant confirmed that the F1 and F2 values of the vowel formants are increased and the direction of movement of the center of gravity of the vowel triangle is statistically significantly forwarded and lowered in the chant method in both the word and the phrase context. The results also proved that accent is the most influential musical factor in chant. There was no significant difference between four repeated tokens, which increased the reliability of the results. In other words, chanting is an effective way to shift the center of gravity of the vowel triangle, which suggests that it can help to improve speech intelligibility by forming a desirable place for articulation.

• Journal of the Korea Computer Industry Society
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• v.2 no.6
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• pp.867-874
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• 2001

In this paper, considering the pronunciation characteristic of Korean, recognition units which can shorten the recognition time and reflect the coarticulation effect simultaneously are suggested. These units are composed of monophone and hipbone ones. Monophone units are applied to the vowels which represent stable characteristic. Biphones are used to the consonant which vary according to adjacent vowel. In the experiment of word recognition of PBW445 database, the compound units result in comparable recognition accuracy with 57％ speed up compared with triphone units and better recognition accuracy with similar speed. In addition, we can reduce the memory size because of fewer units.

• Speech Sciences
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• v.9 no.3
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• pp.201-210
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• 2002

This paper explores whether there is correlation between consonants' place and duration of adjacent vowels in English and Korean. The results showed that in English the vowels preceding alveolar stops were in general longer than the vowels before bilabial or velar stops. Consonants appeared to have their inherent length due to their place and to exhibit some compensatory effects on the duration of preceding vowels. This effect can be explained in a physiological term that the tongue tip is the organ which might be more agile in articulatory movement than the tongue body for the velars or the lower lip (and the jaw) for the bilabials is and the shorter production time of the alveolars caused the lengthening of the adjacent vowels. However, this physiological account did not hold in the case of Korean, which exhibited less consistent patterns across speakers for the consonants' place and the vowel duration. The segmental duration seemed to be timed quite consistently within a language but the pattern was not universal across languages.

• MALSORI
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• no.33_34
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• pp.43-55
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• 1997

This study examined one of the hypotheses on the consonant reduction in Korean inferred from the Articulatory Phonology framework through phonetic experiments: Degree of consonant reduction depends on the height of the neighboring vowels--the lower the height of the neighboring vowel is, the higher the degree of reduction of stop closure period is. The results of this study, in general, turned out to support the hypothesis with some cases requiring other phonetic considerations, e.g., rate of some tongue tip movement in the case of dental lenis stop /t/ or the facts that bilabial lenis stop /p/ share its primary articulators, lips, with the neighboring vowel /u/ and that for bilabial closure, the upper lip lowers more for compensation of little movement of lower lip when its raising gets disturbed for some reasons.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.3-6
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• 1999

합성음의 자연성은 운율(prosody)과 관계가 있으며, 운율은 지속시간(duration), 세기(intensity), 피치(pitch)의 3가지 요소가 어우러져 이루어진다. 본 연구에서는 한국어 여성 음에 나타나는 지속시간 패턴을 분석하여 지속시간의 규칙을 정리함을 목적으로 한다. 본 연구에서는 각 음소(자음, 모음)의 고유 지속시간과 단어내의 음절 위치, 인접음소의 영향, 구와 절의 경계의 영향에 따른 지속시간의 변화를 조사하여 지속시간 규칙을 정립하였다 청취 실험 결과, 본 지속시간 규칙이 합성음의 자연성을 향상시켰다는 것을 보여준다.

• KIISE Transactions on Computing Practices
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• v.21 no.10
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• pp.631-638
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• 2015

Today, the demand for speech recognition systems in mobile environments is increasing rapidly. This paper proposes a novel method for Korean phoneme segmentation that is applicable to a phoneme based Korean speech recognition system. First, the input signal constitutes blocks of the same size. The proposed method is based on a volatility indicator calculated for each block of the input speech signal, and the bulk indicators calculated for each bulk in blocks, where a bulk is a set of adjacent samples that have the same sign as that of the primitive indicators for phoneme segmentation. The input signal vowels, voiced consonants, and voiceless consonants are sequentially recognized and the boundaries among phonemes are found using three devoted recognition algorithms that combine the two types of primitive indicators. The experimental results show that the proposed method can markedly reduce the error rate of the existing phoneme segmentation method.