• Phonetics and Speech Sciences
• /
• v.10 no.2
• /
• pp.45-50
• /
• 2018

The vowel/consonant ratio is a well-known cue for the voicing of postvocalic consonants. This study investigates how this ratio changes as a function of speaking rate. Seven speakers of North American English read sentences containing target monosyllabic words that contrasted in coda voicing at three different speaking rates. Duration measures were taken for the voice onset time (VOT) of the onset consonant, the vowel, and the coda. The results show that the durations of the onset VOT and vowel are longer before voiced codas, and that the durations of all segments increase monotonically as speaking rate decreases. Importantly, the vowel/consonant ratio, a primary acoustic cue for coda voicing, was found to pattern asymmetrically for voiced and voiceless codas; it increases for voiced codas but decreases for voiceless codas with the decrease in speaking rate. This finding suggests that there is no stable ratio in the duration of preconsonantal vowels that is maintained in different speaking styles.

• Speech Sciences
• /
• v.8 no.4
• /
• pp.185-191
• /
• 2001

This study was designed to determine what components of spoken language have been relatively neglected in the teaching of listening comprehension in Korea and to suggest a model of listening process. Two types of tests were undertaken using spoken and written forms of English with secondary school teachers of English and college students. Findings: Hearing power has been generally neglected in the teaching of listening comprehension. Hearing power which can be thought as an active process is defined as an ability to transfer the sequence of discrete phonetic segments without word boundary into the sequence of words in phonemic representations by using both nonlinguistic factors and linguistic factors including perception rules based on phonetics and phonology. Vocabularies, hearing-speaking power, syntactic structures and idiomatic expressions are to be taught for spoken English. A model of listening process was suggested and discussed.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.77-86
• /
• 2009

This study observes how the combined intervention program effects on the acquisition reading pronunciation of Korean phonological process words and the acquisition aspects of each phonological process rules to four Korean learners whose first language is Chinese. The training program is the combination of multisensory Auditory, Visual and Kinethetic (AVK) approach, wholistic approach, and metalinguistic approach. The training purpose is to evaluate how accurately they read the words of the phonological process which have fortisization, nasalization, lateralization, intermediate sound /ㅅ/ (/${\int}iot"$/). We access how they read the untrained words which include the four factors above. The intervention effects are analyzed by the multiple probe across subjects design. The results indicate that the combined phonological process rule explanation and the words activity intervention affects the four Chinese subjects in every type of word. The implications of the study are these: First, it suggests the effect of Korean pronunciation intervention in a concrete way. Second, it offers how to evaluate the phonological process and how to train people who are learning Korean language.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.69-73
• /
• 2009

This paper proposes an efficient global covariance-based principal component analysis (GCPCA) for speaker identification. Principal component analysis (PCA) is a feature extraction method which reduces the dimension of the feature vectors and the correlation among the feature vectors by projecting the original feature space into a small subspace through a transformation. However, it requires a larger amount of training data when performing PCA to find the eigenvalue and eigenvector matrix using the full covariance matrix by each speaker. The proposed method first calculates the global covariance matrix using training data of all speakers. It then finds the eigenvalue matrix and the corresponding eigenvector matrix from the global covariance matrix. Compared to conventional PCA and Gaussian mixture model (GMM) methods, the proposed method shows better performance while requiring less storage space and complexity in speaker identification.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.55-62
• /
• 2009

This paper proposes an improved method to verify a keyword segment that results from a word spotting system. First a baseline word spotting system is implemented. In order to improve performance of the word spotting systems, we use a two-pass structure which consists of a word spotting system and an utterance verification system. Using the basic likelihood ratio test (LRT) based utterance verification system to verify the keywords, there have been certain problems which lead to performance degradation. So, we propose a method which uses phone-level log-likelihood ratios (PLLR) patterns in computing confidence measures for each keyword. The proposed method generates weights according to the PLLR patterns and assigns different weights to each phone in the process of generating confidence measures for the keywords. This proposed method has shown to be more appropriate to word spotting systems and we can achieve improvement in final word spotting accuracy.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.9-22
• /
• 2009

This paper first presents the author's personal view on the importance of modeling in scientific research in general, and then describes two of his works toward modeling certain aspects of human speech communication. The first work is concerned with the physiological and physical mechanisms of controlling the voice fundamental frequency of speech, which is an important parameter for expressing information on tone, accent, and intonation. The second work is concerned with the cognitive processes involved in a discrimination test of speech stimuli, which gives rise to the phenomenon of so-called categorical perception. They are meant to illustrate the power of models based on deep understanding and precise formulation of the functions of the mechanisms/processes that underlie observed phenomena. Finally, it also presents the author's view on some models that are yet to be developed.

• Phonetics and Speech Sciences
• /
• v.1 no.1
• /
• pp.25-31
• /
• 2009

The purpose of this paper is to examine the viability of synthesizing Masan dialect with Seoul dialect and to examine the role of prosody in the authentication of the synthesized Masan dialect. The synthesis was performed by transferring one or more of the prosodic features of the Masan utterance onto the Seoul utterance. The hypothesis is that, given an utterance composed of the phonemes shared by both dialects, as more prosodic features of the Masan utterance are transferred onto the Seoul utterance, the Seoul utterance will be identified as more authentic Masan utterance. The prosodic features involved were the fundamental frequency contour, the segmental durations, and the intensity contour. The synthesized Masan utterances were evaluated by thirteen native speakers of Masan dialect. The result showed that the fundamental frequency contour and the segmental durations had main effects on the perceptual shift from Seoul to Masan dialect.

• Phonetics and Speech Sciences
• /
• v.6 no.2
• /
• pp.3-8
• /
• 2014

This paper deals with how mental fatigue has an effect on human voice. For this a monotonous task to increase the feeling of the fatigue and a set of subjective questionnaire for rating the fatigue were designed. From the experiments the designed task was proven to be monotonous based on the results of the questionnaire responses. To investigate a statistical relationship between speech features extracted from the collected speech data and fatigue, the T test for two-related-samples was used. Statistical analysis shows that speech parameters deeply related to the fatigue are the first formant bandwidth, Jitter, H1-H2, cepstral peak prominence, and harmonics-to-noise ratio. According to the experimental results, it can be seen that voice is changed to be breathy as mental fatigue proceeds.

• Phonetics and Speech Sciences
• /
• v.6 no.2
• /
• pp.115-121
• /
• 2014

This paper investigates the relationship between acoustic characteristics and voice handicap index for 29 males with esophageal speakers. Acoustic characteristics were measured by using a sustained vowel /a/ three times. The stable vocalization for 2 seconds was analyzed by MDVP program. Specifically, relationships between four VHI scores (total, functional, physical, and emotional) and three acoustic characteristics (jitter, shimmer, and NHR) were investigated using the Pearson correlation coefficient. As results, we found no relationship between NHR and VHI scores. However, both jitter and shimmer had statistically significant correlations with all four VHI scores. This research will contribute to establishing a baseline related to speech characteristics in voice rehabilitation with esophageal speakers. Further research could be done to examine the overall quality of life survey, which is widely used as a subjective measure about voice for patients with esophageal speakers.

• Phonetics and Speech Sciences
• /
• v.6 no.2
• /
• pp.107-114
• /
• 2014

MDVP and Praat are measured by nine variables in common; F0, jitter local, jitter absolute, jitter relative average perturbation, jitter period perturbation quotient, shimmer local, shimmer dB, shimmer amplitude perturbation quotient, and NHR. In the present study, 30 female subjects were divided by their disorders(control group, vocal nodule group), ages(from 18 to 50 years old), gender(women), and severities of voice disorder(GRBAS-G0, G1, G2). Then, the subjects' vowel /a/ was evaluated by MDVP and Praat. First, jitter and shimmer variables of the MDVP were significantly different by severities. Praat showed different jitter, shimmer, and NHR parameters by severities. Second, jitter and NHR levels of MDVP were meaningfully higher than Praat regardless their severities. The result of the research confirms the relationships among GRBAS, MDVP and Praat as well as the differences in acoustic variables between MDVP and Praat.