• Phonetics and Speech Sciences
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• v.9 no.4
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• pp.35-41
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• 2017

The existence and the extent of vowel length difference before voiced/voiceless consonants in English and Korean are examined in three groups: (1) Korean-speaking Americans (group A), (2) immigrants who moved to the U.S. in their early teens (group I), and (3) Koreans who have been in the U.S. for less than 3 years (group K). 14 subjects were recorded reading 10 English and 10 Korean sentences. The results show that the three groups exhibit different patterns of the vowel length difference: Group A shows a very strong tendency of vowel lengthening before voiced consonants in both English and Korean, while Group I shows less degree of vowel lengthening, and Group K shows almost no tendency of vowel length difference in both languages. This strongly suggests that, (1) unlike English, Korean does not have the vowel length difference depending on the following consonants, and (2) the vowel lengthening effect observed in Korean (L2) speech in group A may be the result of transfer of the phonetic trait acquired in English (L1). It also implies that, in teaching pronunciation, some facts such as the vowel length difference cannot be expected to be acquired automatically for the learners of English, but have to be taught explicitly.

• Korean Journal of English Language and Linguistics
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• v.3 no.3
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• pp.427-452
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• 2003

Korean is famous for having all voiceless stop sounds. Korean does have voiced stops but they are considered to exist only as the allophones of word initial /p, t, k/. My experiment shows the English word initial stop sounds [b, d, g] and the Korean lax stop series /p, t, k/ in word initial position are similar in the range of voice onset time. If English word initial[b, d, g] sounds are posited as voiced, then Korean word initial /p, t, k/ should be classified as voiced also. Phonetically English /b, d, g/ phonemes and Korean /p, t, k/ phonemes are very similar except the word initial [p, t, k] are devoiced slightly more, but not significant enough to be classified as voiceless than English word initial [b, d, g]. If we posit /b, d, g/ as Korean phonemes, it explains why Korean /p, t, k/ series has the allophones [b, d, g] instead of fortis stops /p', t', k'/ in Korean even though /p', t', k'/ has less positive VOT value than /p, t, k/. If we posit /b, d, g/ as Korean phonemes, then it does not cause spelling or pronunciation confusion either when Koreans learn English or English speakers learn Korean.

• 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.

• The KIPS Transactions:PartB
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• v.9B no.2
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• pp.223-230
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• 2002

In a speech coding system using excitation source of voiced and unvoiced, it would be involves a distortion of speech waveform in case coexist with a voiced and an unvoiced consonants in a frame. This paper present a new method of TSIUVC (Transition Segment Including Unvoiced Consonant) approximate-synthesis by using Least Mean Square. The TSIUVC extraction is based on a zero crossing rate and IPP (Individual Pitch Pulses) extraction algorithm using residual signal of FIR-STREAK Digital Filter. As a result, This method obtain a high Quality approximation-synthesis waveform by using Least Mean Square. The important thing is that the frequency signals in a maximum error signal can be made with low distortion approximation-synthesis waveform. This method has the capability of being applied to a new speech coding of Voiced/Silence/TSIUVC, speech analysis and speech synthesis.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.5
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• pp.111-117
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• 2008

In this paper, we propose an approach to improve the performance of voiced/unvoiced (V/UV) decision under background noise environments for the selectable mode vocoder (SMV) of 3GPP2. We first present an effective analysis of the features and the classification method adopted in the SMV. And then feature vectors which are applied to the GMM are selected from relevant parameters of the SMV for the efficient voiced/unvoiced classification. For the purpose of evaluating the performance of the proposed algorithm, different experiments were carried out under various noise environments and yields better results compared with the conventional scheme of the SMV.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.6
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• pp.1175-1179
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• 2006

In a speech coding system using excitation source of voiced and unvoiced, it would be a distortion of speech waveform in case of exist a voiced and an unvoiced consonants in a frame. In this paper, I propose a new method of TSIUVC(Transition Segment Including Unvoiced Consonant) approximate-synthesis by using Least Mean Square. As a result, a method by using Least Mean Square was obtained a high quality approximation-synthesis waveform . The important thing is that the frequency signals in a maximum error signal can be made with low distortion approximation-synthesis waveform. This method has the capability of being applied to a new speech coding of Voiced/Silence/TSIUVC, speech analysis and synthesis.

• MALSORI
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• no.58
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• pp.67-81
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• 2006

For a large corpus of time-aligned data, HMM based approaches are most widely used for automatic segmentation, providing a consistent and accurate phone labeling scheme. There are two methods for training in HMM. Flat starting method has a property that human interference is minimized but it has low accuracy. Bootstrap method has a high accuracy, but it has a defect that manual segmentation is required In this paper, a new algorithm is proposed to minimize manual work and to improve the performance of automatic segmentation. At first phase, voiced, unvoiced and silence classification is performed for each speech data frame. At second phase, the phoneme sequence is aligned dynamically to the voiced/unvoiced/silence sequence according to the acoustic phonetic rules. Finally, using these segmented speech data as a bootstrap, phoneme model parameters based on HMM are trained. For the performance test, hand labeled ETRI speech DB was used. The experiment results showed that our algorithm achieved 10% improvement of segmentation accuracy within 20 ms tolerable error range. Especially for the unvoiced consonants, it showed 30% improvement.

• Phonetics and Speech Sciences
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• v.10 no.4
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• pp.135-146
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• 2018

The Modified Voiced Lip Trill (MVoLT) training is a variant of voiced lip-till training characterized by increased loudness, lowered laryngeal position, and lip contact facilitated with fingers. The purpose of the current study was to assess the effect of the MVoLT training program on vocal changes of musical singing theater students. A total of 32 musical theater students (17 males and 15 females, age ranging from 18 to 29) participated in the study. For about three months, each participant was tutored using a systematic program focussing on the MVoLT training, accompanied by certain facilitating strategies. Pre- & post-training multi-dimensional vocal characteristics were assesed and compared. Results showed that cepstral peak prominence during vowel phonation increased after training, while its standard deviation and Cepstral Spectral Index of Dysphonia decreased. When an aerodynamic assessment was performed, maximum phonation time, subglottal pressure, mean airflow rate increased, while electroglottographic measures did not change. In addition, decreased psychometric measures, higher maximum pitch, and increased vocal range were noted after training. In conclusion, the MVoLT was proven to have a potential as an effective and safe training method for musical theater singing.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.18 no.6
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• pp.1294-1301
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• 2014

In this paper, separate probabilistic distribution models for voiced and unvoiced speech are estimated and utilized to improve speaker recognition performance. Also, in addition to the conventional mel-frequency cepstral coefficient, skewness, kurtosis, and harmonic-to-noise ratio are extracted and used for voiced speech intervals. Two kinds of scores for voiced and unvoiced speech are linearly fused with the optimal weight found by exhaustive search. The performance of the proposed speaker recognizer is compared with that of the conventional recognizer which uses mel-frequency cepstral coefficient and a unified probabilistic distribution function based on the Gassian mixture model. Experimental results show that the lower the number of Gaussian mixture, the greater the performance improvement by the proposed algorithm.

• The Journal of the Acoustical Society of Korea
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• v.42 no.4
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• pp.298-303
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• 2023

This study aimed to investigate the clinical utility of voiced sentence tasks for voice evaluation. To this end, we analyzed the correlation between perturbation-based acoustic measurements [jitter percent (jitter), shimmer percent (shimmer), Noise to Harmonic Ratio (NHR)] using sustained vowel phonation, and cepstrum-based acoustic measurements [Cepstral Peak Prominence (CPP), Low/High spectral ratio (L/H ratio)] using voiced sentences. As a result of analyzing data collected from 65 patients with voice disorders, there was a significant correlation between the CPP and jitter (r = -.624, p = .000), shimmer (r = -.530, p = .000), NHR (r = -.469, p = .000).This suggests that the cepstrum measurement of voiced sentences can be used as an alternative to the analysis limitations of the pathological voice such as not possible perturbation-based acoustic measurement, and result difference according to the analysis section.