• Proceedings of the KSPS conference
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• 2007.05a
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• pp.211-212
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• 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 the Korea Institute of Information and Communication Engineering
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• v.18 no.7
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• pp.1740-1748
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• 2014

This paper focuses on listening test and acoustic analysis of patients' speech with velopharyngeal insufficiency (VPI) and normal speakers' simulation speech. In this research, a set consisting of 50-words, vowels and single syllables is determined for speech database construction. A web-based listening evaluation system is developed for a convenient/automated evaluation procedure. The analysis results show the trend of incorrect recognition for VPI speech and the one for simulation speech are similar. Such similarity is also confirmed by comparing the formant locations of vowel and spectrum of consonant sounds. These results show that the simulation method for VPI speech is effective at generating the speech signals similar to actual VPI patient's speech. It is expected that the simulation speech data can be effectively employed for our future work such as acoustic model adaptation.

• The Journal of the Acoustical Society of Korea
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• v.23 no.2
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• pp.162-172
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• 2004

This study investigates the following three things through a production experiment and acoustic analysis: 1) relationship between speech rate and the segment duration in Korean, 2) relationship between speech rate and spectral characteristics of vowels, i. e. undershoot, and 3) correlation between the vowel duration and undershoot. The results showed that the faster the speech rate nab, the shorter the duration of syllables and segments was. A few speakers were affected by speech rate in the durational ratios between closure and aspiration in a stop and between Towel and consonant in a syllable. Closure duration and vowel duration were more affected compared to aspiration and consonant duration, respectively. Speakers showed some differences in the extent to which speech rate affected vowel undershoot, implying that speakers used different production mechanisms for spectral characteristics of vowels: Some speakers speeded up movement of articulatory organs according to speech rate increase while some kept it constant regardless of speech rate change.

• 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.

• Phonetics and Speech Sciences
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• v.10 no.1
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• pp.65-74
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• 2018

The purpose of this study is to investigate age-specific features of 2;1- to 4;1-year -olds' production of monophthongs and diphthongs through both auditory perceptual analysis and acoustic analysis. Test material included {vowel+'da'} consisting of 7 monophthongs and 10 diphthongs and meaningful words beginning with vowels. The percentage of correct vowels was used for perceptual analysis and Praat(5.2.12) was used for acoustic analysis, analyzing variables related to monophthongs and diphthongs. The results of this study are as follows: First, perceptual analysis showed that children from an age group of 2;1 to 2;8 years showed significant difference in the accuracy level of both monophthongs and diphthongs as compared to those aged 2;9 to 3;4 years and those aged 3;5 to 4;1 years. Second, the results of acoustic analysis provided that formant (F1 and F2) of monophthong, in general, tended to decrease as age increased. In terms of F2 differentiation slope and regression slope, which were diphthong-related variables, the age group of 3;5 to 4;1 years showed a large general slope change.

• Journal of radiological science and technology
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• v.20 no.1
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• pp.21-27
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• 1997

Total laryngectomy has become an usual treatment for any advanced carcinoma of the laynx, but most patients who have undergone total laryngectomy have shown permanant disability in voice production. I compared the first three formant frequencies estimated from MRI to those measured directly from speech data of the T-E patients and the normal. It was to estimate the accuracy of MRI and to compare the vocal tract shape of the normal to T-E patients. The obtained results were as follows : 1. The middle sagittle section of the MRI represents vocal tract well during pnonation. The vocal tract shape of the T-E shunt patients are lack of pharyngeal space and superior space of the glottis. 2. The length of the normal subject's vocal tract is 17 cm. For the T-E shunt patients, the length from lip to shunt opening is 17.5 cm in case 1, and 18.5 cm in case 2. That of the true resonante chamber is 13 cm and 13.5 cm for each case respectively. 3. T-E shunt patients phonated strained voice. The intensity of the higher formant frequency decreased especially in /o/, /u/. 4. The vocal tract is shortened during the phonation by T-E shunt patients. In case of /e/ and /i/, front cavities are constricted while back cavities are shortened. 5. The pseudoglottis of the T-E shunt patients is located at $14{\sim}15\;cm$ below from lips.

• Proceedings of the KSPS conference
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• 2000.07a
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• pp.86-87
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• 2000

In this paper, we discuss why two different surface forms appear in loanwords for English and German /${\int}$/ In Korean, a vowel is inserted into loanwords if a consonant cannot be properly syllabified. Therefore, /${\int}$/ in some positions of loanwords trigger vowel insertion. Interestingly, /${\int}$/s in the onset cluster of English and German words were borrowed in Korean as Iful with the inserted vowel [u] whereas If Is in the coda position of English and German words were borrowed as Ifil with the inserted vowel [i]. For example, 'shrimp' is adopted as [${\int}urimphi$] whereas 'rush' is adopted as [$ra{\int}i$]. In this paper, we attempt to find out the phonetic reason for the distribution of the surface forms of /${\int}$/. We assume that since the formant frequency of [i] is higher than that of [u], the peak frequency of /${\int}$/ with the surface form of [${\int}$i] in loanwords may be higher than that of /${\int}$/ with the surface form of [${\int}u$]. We also assume that duration may be another factor for the distribution of [${\int}i$] and [${\int}u$]. Since /${\int}$/ and /u/ use lip rounding whereas /i/ doesn't, the duration for [${\int}i$] might be longer than that of [${\int}u$]. German supports our assumption. /${\int}$/ in the onset cluster is longer than /${\int}$/ in the coda position. It also has higher peak frequency than that of /${\int}$/ in the coda position. In loanwords, ${\int}$ in the onset cluster is borrowed as [${\int}u$] as in Spiegel whereas /${\int}$/ in the coda position is borrowed as [${\int}i$] as in Bosch. English, however, does not support our assumption. Peak frequency of [${\int}$] depends on the preceding vowel, not on its position in the syllable structure. If the preceding vowel is front, then the peak freuency of the following of the following /${\int}$/ is high but if the preceding vowel is back, than the peak frequency of the following /${\int}$/ is low. The peak frequency of /${\int}$/ in the onset cluster seems to be in between. As we assumed, however, the duration of /${\int}$/ in the coda position is longer than of /${\int}$/ in the onset cluster. With the mixed results, we question whether Koreans really hear two different xounds for /${\int}$/ in English words. For the future experiment, we would like to perform the perception tet for /${\int}$/ in English words.

• 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.3 no.2
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• pp.53-61
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• 2011

The present work is a follow-up study to that of Han, Choi, Lim and Lee (2011), where an asymmetry in the source segments eliciting the interlanguage speech intelligibility benefit (ISIB) was found such that the vowels which did not match any vowel of the Korean language were likely to elicit more ISIB than matched vowels. In order to identify the source of the stronger ISIB in non-matched vowels, acoustic analyses of the stimuli were performed. Two pairs of English front vowels [i] vs. [I], and $[{\varepsilon}]$ vs. $[{\ae}]$ were recorded by English native talkers and two groups of Korean learners according to their English proficiency, and then their vowel duration and the frequencies of the first two formants (F1, F2) were measured. The results demonstrated that the non-matched vowels such as [I], and $[{\ae}]$ produced by Korean talkers seemed to show more deviated acoustic characteristics from those of the natives, with longer duration and with closer formant values to the matched vowels, [i] and $[{\varepsilon}]$, than those of the English natives. Combining the results of acoustic measurements in the present study and those of word identification in Han et al. (2011), we suggest that relatively better performance in word identification by Korean talkers/listeners than the native English talkers/listeners is associated with the shared interlanguage of Korean talkers and listeners.

• Speech Sciences
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• v.6
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• pp.197-217
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• 1999

In a noisy class, the acoustic-phonetic features of the teacher and the perceptual features of learners are changed comparison with a quiet environment. Acoustical analyses were carried out on a set of French monosyllables consisting of 17 consonants and three vowel /a, e, i/, produced by 1 male speaker talking in quiet and in 50, 60 and 70 dB SPL of masking noise on headphone. The results of the acoustic analyses showed consistent differences in energy and formant center frequency amplitude of consonants and vowels, $F_1$ frequency of vowel and duration of voiceless stops suggesting the increase of vocal effort. The perceptual experiments in which 18 undergraduate female students learning French served as the subjects, were conducted in quiet and in 50, 60 dB of masking noise. The identification scores on consonants were higher in Lombard speech than in normal speech, suggesting that the speaker's vocal effort is useful to overcome the masking effect of noise. And, with increased noise level, the perceptual response to the French consonants given had a tendency to be complex and the subjective reaction score on the noise using the vocabulary representative of 'unpleasant' sensation to be higher. And, in the point of view on the L2(second language) acquisition, the influence of L1 (first language) on L2 examined in the perceptual result supports the interference theory.