• Speech Sciences
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• v.7 no.2
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• pp.37-50
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• 2000

This paper describes a test of everyday speech understanding ability, in which a listener's utilization of the context-situational information of speech is assessed, and is compared with the utilization of acoustic-phonetic information. The test items are sentences which are presented in a babble type of noise, and the listener response is the key word in the sentence. The key words are always two-syllabic nouns and the questioning sentences are added to obtain the responding key words. Two types of sentences are used. One is the high-predictable sentences for which the key word is somewhat predictable from the context. The other is the low-predictable sentences for which the key-word cannot be predicted from the context. Both types are included in six 40-item forms of the test, which are balanced for intelligibility, key-word familiarity and predictability, phonetic content, and length. Performance of normally hearing listeners shows significantly different functions for various signal-to-noise ratios. The potential applications of this test, particularly in the assessment of speech understanding ability in the hearing impaired, are discussed.

• Phonetics and Speech Sciences
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• v.2 no.4
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• pp.213-221
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• 2010

The number of North Korean refugees entering South Korea is continuously increasing. North Korean speakers show significant differences in vowel and consonant phonetics, length of vowels, and the rhythm and intonation of sentences. The object of this research was to examine the effectiveness of a speech intervention program for North Korean refugees using visual feedback through acoustical analysis for intonation. The subjects were three adults with no speech disabilities who had been in South Korea for less than five years. They had not received any prior treatment for inflection change. The program was set in a discourse situation and used Praat to evaluate intonation and provide visual feedback as demonstrating proper intonation changes through pitch contour. The results after intervention are as follows. First, intonation was significantly improved according to a 5-point subjective evaluation scale. Second, the pitch contour was similar to the contour of standard South Korean pronunciation. The subjects were very satisfied with this initial treatment and showed a high level of motivation. In subsequent study, the development of intervention and the comparison of interventions will be needed as well.

• Journal of the Institute of Convergence Signal Processing
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• v.7 no.4
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• pp.178-183
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• 2006

As a lot of researches on the speech signal processing are performed due to the recent rapid development of the information-communication technology. the pitch period is used as an important element to various speech signal application fields such as the speech recognition. speaker identification. speech analysis. or speech synthesis. A variety of algorithms for the time and the frequency domains related with such pitch period detection have been suggested. One of the pitch detection algorithms for the time domain. AMDF (average magnitude difference function) uses distance between two valley points as the calculated pitch period. However, it has a problem that the algorithm becomes complex in selecting the valley points for the pitch period detection. Therefore, in this paper we proposed the modified AMDF(M-AMDF) algorithm which recognizes the entire minimum valley points as the pitch period of the speech signal by using the rotation transform of AMDF. In addition, a threshold is set to the beginning portion of speech so that it can be used as the selection criteria for the pitch period. Moreover the proposed algorithm is compared with the conventional ones by means of the simulation, and presents better properties than others.

• Phonetics and Speech Sciences
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• v.11 no.3
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• pp.57-67
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• 2019

This study aimed to investigate regional differences in the development of speech production in Korean children. A total of 619 children aged 2 to 7 years from the Jeolla, Seoul/Gyeonggi, Chungcheong, and Gyeongsang areas were included in this study. The subjects were assessed with the UTAP2 word-level test. In PWC, PMLU, and PWP, the performance was significantly lower in Gyeongsang at 2 years 11 months and in Jeolla and Chungcheong at 3 years 5 months than in Seoul/Gyeonggi. The total PCC of Gyeongsang and Chungcheong and UTAP PCC of Chungcheong were significantly lower at 2 years 11 months compared with those of Seoul/Gyeonggi, while Jeolla and Chungcheong showed significantly lower total PCC and UTAP PCC than Seoul/Gyeonggi at 3 years 5 months. However, no regional difference was observed in any indicators after the age of 3 years 6 months. These results suggest that there are regional differences in the ability to produce speech sounds at a very young age, and that the differences can be explained by the differences between Seoul/Gyeonggi and the other provinces rather than by the individual characteristics of specific regions.

• Journal of the Korean Institute of Intelligent Systems
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• v.22 no.6
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• pp.681-686
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• 2012

This paper studied the speech parameters less affected by the human emotion for the development of the robust emotional speech recognition system. For this purpose, the effect of emotion on the speech recognition system and robust speech parameters of speech recognition system were studied using speech database containing various emotions. In this study, mel-cepstral coefficient, delta-cepstral coefficient, RASTA mel-cepstral coefficient, root-cepstral coefficient, PLP coefficient and frequency warped mel-cepstral coefficient in the vocal tract length normalization method were used as feature parameters. And CMS (Cepstral Mean Subtraction) and SBR(Signal Bias Removal) method were used as a signal bias removal technique. Experimental results showed that the HMM based speaker independent word recognizer using frequency warped RASTA mel-cepstral coefficient in the vocal tract length normalized method, its derivatives and CMS as a signal bias removal showed the best performance.

• The Journal of the Acoustical Society of Korea
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• v.13 no.1
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• pp.24-31
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• 1994

In this paper, we report on the development of a speaker independent continuous speech recognition system using continuous hidden Markov models. The continuous hidden Markov model consists of mean and covariance matrices and directly models speech signal parameters, therefore does not have quantization error. Filter bank coefficients with their 1st and 2nd-order derivatives are used as feature vectors to represent the dynamic features of speech signal. We use the segmental K-means algorithm as a training algorithm and triphone as a recognition unit to alleviate performance degradation due to coarticulation problems critical in continuous speech recognition. Also, we use the one-pass search algorithm that Is advantageous in speeding-up the recognition time. Experimental results show that the system attains the recognition accuracy of $83\%$ without grammar and $94\%$ with finite state networks in speaker-indepdent speech recognition.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.42 no.2 s.302
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• pp.131-142
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• 2005

The low rate speech coders under 4 kbit/s are based on sinusoidal transform coding (STC) or multiband excitation (MBE). Since the harmonic coders are not efficient to reconstruct the transient segments of speech signals such as onsets, offsets, non-periodic signals, etc, the coders do not provide a natural speech quality. This paper proposes method of a efficient transient model :d a multi-mode low rate coder at 2.4 kbit/s that uses harmonic model for the voiced speech, stochastic model for the unvoiced speech and a model using aperiodic pulse location tracking (APPT) for the transient segments, respectively. The APPT utilizes the harmonic model. The proposed method uses different models depending on the characteristics of LPC residual signals. In addition, it can combine synthesized excitation in CELP coding at time domain with that in harmonic coding at frequency domain efficiently. The proposed coder shows a better speech quality than 2.4 kbit/s version of the mixed excitation linear prediction (MELP) coder that is a U.S. Federal Standard for speech coder.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.85-95
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• 2020

Sentence repetition is a way of evaluating speech sound production to improve the limitation of word tests and spontaneous speech analysis. Speech sounds produced by children can be evaluated using several indicators. This study examined the progression of the percentage of correct consonants-revised (PCC-R) and phonological whole-word measure in different age and gender groups after setting consonants in various vowel contexts and implementing sentence repetition tasks that were designed to give all phonemes the chance to appear at least three times. For this study, 11 sentence repetition tasks were applied to 535 children aged 3 to 7 across the country, after which the resulting PCC-R and whole-word measure were analyzed. The study results showed that all the indicators improved in older age groups and there were significant differences depending on age, however, no significant differences dependent on gender were found. The sentence repetition conditions data used in this study were collected from across the country, and the age difference between each age group was six months. This study is noteworthy because it collected a sufficient amount of data from each group, highlighted the limitation of the word naming and the spontaneous speech analysis, and suggests new criteria of evaluation through the analysis of each whole-word measure in sentence repetition, which was not applied in previous studies.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1972.03a
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• pp.2.1-2
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• 1972

The development of our social life and standard of living should stimulate our concern not only of primary treatment of disease, but also of rehabilitation and social welfare. We ordinarily understand that rehabilitation is limited to the rehabilitation of bodies, and yet development of a speech rehabilitation program is also neccessary at the same time. One of the pollutions, the "speech pollution" should be given attention, as so many children are pronouncing words incorrectly due to the fact that they are influenced by mass communication and the wrong pronounciation of the adult. We have studies the pronounciation of 921 boys and girls of five primary schools in Chonju City, and this paper is dealing with the method of study, its result, and its casuses. It is hoped that this paper will stimulate further study of speech pathology in Korea and will help eliminate "speech pollution" of the children.

• Phonetics and Speech Sciences
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• v.6 no.2
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• pp.65-71
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• 2014

The purpose of this study was to investigate whether young children with cleft palate differ from those of noncleft typically developing children in terms of expressive vocabulary size, phonological characteristics and lexical selectivity. A total of 12 children with cleft palate and 12 noncleft children who were matched by age and gender participated in the study. The groups were compared by size of expressive vocabulary reported on Korean version of MacArthur-Bates Communicative Development Inventories and the number of different words, consonant inventory, the percentage of words beginning with obstruents and vowels, nasal, and glottal sounds, and the percentage of words which do not include obstruents in a language sample. Also, correlation analysis were performed to examine the relationship between measures on size of expressive vocabulary and phonological characteristics. The results showed that expressive vocabulary size and consonant inventory for children with cleft palate produced significantly smaller than those for noncleft children. Children with cleft palate produced significantly more words beginning with vowel or which do not include obstruents, and fewer words beginning with obstruents than noncleft children. The two groups showed different results on significant correlations between measures on size of expressive vocabulary and phonological characteristics indicating that children with cleft palate show different lexical selectivity from their noncleft peers. The results suggest that children with cleft palate aged 18-30 months demonstrate a slower rate of lexical and phonological development compared with their noncleft peers and they develop lexical selectivity reflecting cleft palate speech. The results will have a clinical implication on speech-language intervention for young children with cleft palates.