• Journal of the Korea Convergence Society
• /
• v.9 no.6
• /
• pp.125-132
• /
• 2018

This study was to investigate the speech sound production characteristics and evaluation aspects of preschool children through word test and connected speech test. For this, the authors conducted Assessment of Phonology and Articulation for Children(APAC) to 72 normal children(24 three-, four-, and five-year-olds each) and analyzed difference in percent of correct consonant(PCC) and intelligibility according to age and sex, correlation between PCC and intelligibility, and speech sound error patterns. PCC and intelligibility increased with age but there was no difference according to sex. The correlation was statistically significant in 5-year-old group. Speech sound error patterns were different in the two tests. This study showed that children's speech sound production varied according to language unit. Therefore, both types of tests should be done to grasp their speech sound production ability properly. This suggests that current standard to identify language impairment only by PCC of word level requires review and further studies.

• Proceedings of the KSPS conference
• /
• 2007.05a
• /
• pp.211-212
• /
• 2007

Stroke makes several physical deficits. Dysarthria is one of the most difficult problems in conventional medicine because of the weakness of neuromotor control. The purpose of this study is to find the acoustic characteristics of acupuncture therapy effects on post-stroke dysarthria. Seven patients with stroke(infarction or hemorrhage) were selected by CT or MR imaging. The authors applied acupuncture therapy by inserting needles into 8 acupuncture points, ipsilateral ST4, ST6 and contralateral LI4, ST36 on facial palsy side, and CV23, CV24, bilateral "Sheyu" for 4 weeks. Speech sample were composed of five simple vowels /a,e,i,o,u/ and meaningless polysyllabic words CVCVC(C: stops, affricated, fricative sounds, v: /e/). .VOT, total duration of each speech samples and vowel formant (F1&F2) were analyzed on Spectrogram. The results are as follows: 1. VOT of bilabial and velar stops was decreased post treatment. The VOT of bilabial glottalized pre and post treatment were statistically significant (p < 0.05). 2. Total duration of polysyllabic words was decreased post treatment. Decrement of total duration containing the bilabial was statistically significant (p<0.05). 3. First formant of round vowel /o/ pre and post treatment was statistically significant (p<0.05).

• Journal of Korea Multimedia Society
• /
• v.9 no.1
• /
• pp.23-32
• /
• 2006

This paper describes the optimization of a language model and an acoustic model to improve speech recognition using Korean unit digits. Since the model is composed of a finite state network (FSN) with a disyllable, recognition errors of the language model were reduced by analyzing the grammatical features of Korean unit digits. Acoustic models utilize a demisyllable pair to decrease recognition errors caused by inaccurate division of a phone or monosyllable due to short pronunciation time and articulation. We have used the K-means clustering algorithm with the transformed successive state splitting in the feature level for the efficient modelling of feature of the recognition unit. As a result of experiments, 10.5% recognition rate is raised in the case of the proposed language model. The demi-syllable fair with an acoustic model increased 12.5% recognition rate and 1.5% recognition rate is improved in transformed successive state splitting.

• The Journal of the Acoustical Society of Korea
• /
• v.13 no.1
• /
• pp.14-23
• /
• 1994

In this paper, speech units appropriate for recognition of Korean language have been studied. For better speech recognition, co-articulatory effects within an utterance should be considered in the selection of a recognition unit. One way to model such effects is to use larger units of speech. It has been found that diphone is a good recognition unit because it can model transitional legions explicitly. When diphone is used, stationary phoneme models may be inserted between diphones. Computer simulation for isolated word recognition was done with 7 word database spoken by seven male speakers. Best performance was obtained when transition regions between phonemes were modeled by two-state HMM's and stationary phoneme regions by one-state HMM's excluding /b/, /d/, and /g/. By merging rarely occurring diphone units, the recognition rate was increased from $93.98\%$ to $96.29\%$. In addition, a local interpolation technique was used to smooth a poorly-modeled HMM with a well-trained HMM. With this technique we could get the recognition rate of $97.22\%$ after merging some diphone units.

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

• The Journal of the Acoustical Society of Korea
• /
• v.30 no.5
• /
• pp.295-302
• /
• 2011

The purpose of this study was to develop Korean Consonant Perception Test (KCPT), that is a phonemic level including elementary data to evaluate speech and consonant perception ability of the normal and the hearing impaired qualitatively and quantitatively. KCPT was completed with meaningful monosyllabic words out of possible all Korean monosyllabic words, considering articulation characteristics, the degree of difficulty, and the frequency of the phonemic appearance, after assembling a tentative initial and final consonants testing items using four multiple-choice method which were applied to the seven final consonant regulation and controlled with the familiarity of the target words. Conclusively, the final three hundred items were developed including two- and one-hundred items for initial and final testing items, respectively, with the evaluation of the 20 normal hearing adults. Through this process, the final KCPT was composed upon the colloquial frequency following identification of no speakers' variances statistically and elimination of the highly difficult items. The 30 hearing impaired were tested with KCPT and found that the half lists, A and B, were not different statistically and the initial and final testing items were appropriate for evaluating initial and final consonants, respectively.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.16 no.2
• /
• pp.118-122
• /
• 2005

Background and Objectives The compensatory articulation not only influences general speech intelligibility, but also prevents precise assessment of the velopharyngeal function. This study was performed to investigate frequently affected phonemes, prevalence and the characteristics of compensatory articulation in the patients with cleft palate having velopharyngeal insufficiency. Material and Method An archival review was taken on 103 cleft palate subjects. Their age ranged from 2.6 to 63 years (mean age of 9.8 years). They were grouped into two : preschool group (n=71) and older patient group (n=32). The prevalence and patterns of compensatory articulation were examined on oral high pressure consonants such as plosives, fricatives and affricates. Results : Compensatory errors were observed in $49.5\%$ of the subjects and were mostly glottal stops with the exception of 4cases who had pharyngeal fricatives in addition to glottal stops. The most frequently substituted phonemes were velar plosives and tense sound. There was no significant difference of prevalence in both groups. However, errors for bilabial and alveolar plosives were more frequently observed in preschool group. Conclusion High prevalence of compensatory articulation observed in both preschool and older age group indicates that their articulation errors tend to remain unless appropriate speech therapy is provided. To improve speech intelligibility of the patients with cleft palate having velopharyngeal insufficiency, it is advisable to address and correct the compensatory articulation errors in their earlier ages.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.19 no.2
• /
• pp.133-135
• /
• 2008

Background and Objectives: The voice changes can occur in peritonsillar abscess and the labeling of this changes as a "muffled voice". The aim of this study was to investigate the changes in acoustic feature of voice before and after treatment in patients with peritonsillar abscess. Materials and Method: 12 patients with peritonsillar abscess were enrolled in the study. Acoustic analysis on sustained Korean vowels /a/, /i/ and /u/ were performed before and after treatment. Results: In patients with peritonsillar abscess, the first formant frequency (F1) and second formant frequency (F2) of /a/ were decreased. There was tendency of articulation of back-low vowel /a/ as back-high vowel /u/. F1 of /i/ and /u/ were increased, while F2 were decreased. There was tendency of articulation of front-high vowel /i/ as back-low vowel /a/. The third, forth, fifth formant frequency (F3, F4, F5) of /a/, /i/ and /u/ were decreased although statistically not significant. Conclusion: The anatomical and functional changes of oropharynx by peritonsillar abscess can cause changes in resonance and speech quality. We suggest that these changes could be the cause of 'muffled voice' in patients of peritonsillar abscess.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
• /
• v.21 no.1
• /
• pp.48-53
• /
• 2010

Backgraound and Objectives : The voice change can occur in acute epiglottitis or peritonsillar abscess, and the labelings of both changes as a "muffled voice" or "hot potato voice", The aim of this study was to investigate the difference of changes in acoustic feature of voice before and after treatment in patients with acute epiglottitis or peritonsillar abscess. Subjects and Method: 13 patients with acute epiglottitis and 12 patients with peritonsillar abscess were enrolled in the study. Acoustic analysis on sustained Korean vowels /${\alpha}$/, /u/ and /i/ were performed before and after treatment. Results: In patients with acute epiglottitis, the first formant frequency (F1) of /${\alpha}$/ was increased, and the second frequency (F2) of /i/ was decreased. In patients with peritonsillar abscess, F1 and F2 of /${\alpha}$/ were decreased. F1 of /i/ and /u/ were increased, while F2 were decreased. Conclusion : The anatomical and functional changes of oropharynx and larynx by acute epiglottitis and peritonsillar abscess can cause different change in resonance and speech quality. We suggest that these changes could be the cause of 'muffled vocie' in patients of acute epiglottitis or peritonsillar abscess, but different characteristics of phonation in each disease should be distinguished.

• Phonetics and Speech Sciences
• /
• v.7 no.2
• /
• pp.19-28
• /
• 2015

This study investigated final consonant error characteristics at word-medial position in children with functional articulation disorder. Data was collected from 11 children with functional articulation and 11 normal children, ages 4 to 5. The speech samples were collected from a naming test. Seventy-five words with every possible bi-consonants matrix at the word-medial position were used. The results of this study were as follows : First, percentage of correct word-medial final consonants of functional articulation disorder was lower than normal children. Second, there were significant differences between two groups in omission, substitution and assimilation error. Children with functional articulation disorder showed a high frequency of omission and regressive assimilation error, especially alveolarization in regressive assimilation error most. However, normal children showed a high frequency of regressive assimilation error, especially bilabialization in regressive assimilation error most. Finally, the results of error analysis according to articulation manner, articulation place and phonation type of consonants of initial consonant at word-medial, both functional articulation disorder and normal children showed a high error rate in stop sound-stop sound condition. The error rate of final consonant at word-medial position was high when initial consonant at word-medial position was alveolar sound and alveopalatal sound. Futhermore, when initial sounds were fortis and aspirated sounds, more errors occurred than linis sound was initial sound. The results of this study provided practical error characteristics of final consonant at word-medial position in children with speech sound disorder.