• Phonetics and Speech Sciences
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• v.3 no.4
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• pp.109-115
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• 2011

The purposes of this study were to identify acoustic parameters of connected speech and to contribute to acoustic analysis of dysphonic voice about patient's natural speech voice as well as sustained phonation of vowels. Acoustic parameters of sentences included LTAS (long-term average spectrum) mean and spectral slope over frequence ranges such as 0-4kHz, 0-6kHz, 0-8kHz, 0-12.5kHz as well as HNR. Acoustic parameters of the vowel 'a' included jitter, RAP, shimmer, NHR, and HNR. Based on 'G' of GRBAS for the severity of dysphonia, two experienced raters judged and classified as four groups including controls, mild, moderate and severe dysphonic group. Connected speech was two sentences extracted from 'stroll' passage. Parameters of the vowel and LTAS mean of the sentences were measured by CSL. The spectral slope of the sentences and HNR of the vowel and the sentences were measured by Praat. Data were statistically analyzed by Spearman correlation and Kruskal-Wallis test using SPSS 12.0. The results of this study are as follows: First, jitter, RAP, shimmer and NHR were significantly different between the groups. Second, for several frequencies, LTAS mean and spectral slope of the sentences were significantly different between the groups. Third, the HNR of the sentences were significantly different between the groups. Forth, there was a presence of correlation between HNR and NHR of the vowel and HNR of the sentences. Accordingly, this study concluded that LTAS, spectral slope, and HNR were predictive parameters of connected speech voice for dysphonic voice.

• Speech Sciences
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• v.15 no.2
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• pp.131-141
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• 2008

The purpose of this study was to find out the acoustic variation on the pre-and post respiration and oral motor for children with cerebral palsy. Five children with spastic CP at the age of 6 in average were practiced by a caregiver at home each for 25 minutes, in total, 45 times. The sustained of vowel /a/ and vowels /a/, /i/, /u/, /e/, /o/ were recorded on CSL and MDVP and analyzed by acoustic parameters. As a result, the maximum phonation time(MPT) was increased from 2.06 to 6.31 and the formant of vowels(F1, F2, F3) had significant differences in F1(/a, i/), F2(/i.u.o/), and F3(/a/) between the controls and the children with CP in pre-treatment. The total average value of vowels had significant differences between the pre-and post-treatment (p< .05). The energy of vowels had significant differences in the vowels /i, u, e, o/ and the total average value between the pre-and post-treatment(p< .001). The jitter percent, shimmer percent, and noise to harmonic ratio had significant differences between the pre-and post-treatment(p< .05). As the respiration and the oral motor improved MPT, voice quality, and articulation of vowel, and the variation of the formant(F1, F2, F3) showed the changes in the shape of lips, the place and the height of the tongue, the various development of therapy programs and the consistent intervention of treatment is needed for the children with cerebral palsy.

• Phonetics and Speech Sciences
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• v.4 no.2
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• pp.61-70
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• 2012

The current study observes the durational interaction of tautosyllabic consonants and vowels in the word-initial position of English and Korean child-directed speech (CDS). The effect of phonological laryngeal contrasts in stops on the following vowel duration, and the effect of the intrinsic vowel duration on the release duration of preceding stops in addition to the acoustic realization of the contrastive segments are explored in different prosodic contexts - phrase-initial/medial, focal accented/non-focused - in a marked speech style of CDS. A trade-off relationship between Voice Onset Time (VOT), as consonant release duration, and voicing phonation time, as vowel duration, reported from adult-to-adult speech, and patterns of durational variability are investigated in CDS of two languages with different linguistic rhythms, under systematically controlled prosodic contexts. Speech data were collected from four native English mothers and four native Korean mothers who were talking to their one-word staged infants. In addition to the acoustic measurements, the transformed delta measure is employed as a variability index of individual tokens. Results confirm the durational correlation between prevocalic consonants and following vowels. The interaction is revealed in a compensatory pattern such as longer VOTs followed by shorter vowel durations in both languages. An asymmetry is found in CV interaction in that the effect of consonant on vowel duration is greater than the VOT differences induced by the vowel. Prosodic effects are found such that the acoustic difference is enhanced between the contrastive segments under focal accent, supporting the paradigmatic strengthening effect. Positional variation, however, does not show any systematic effects on the variations of the measured acoustic quantities. Overall vowel duration and syllable duration are longer in English tokens but involve less variability across the prosodic variations. The constancy of syllable duration, therefore, is not found to be more strongly sustained in Korean CDS. The stylistic variation is discussed in relation to the listener under linguistic development in CDS.

• Speech Sciences
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• v.7 no.3
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• pp.197-218
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• 2000

The vocal tract shapes were measured from tracheoesophageal speakers during the sustained phonation of five Korean vowels /u/, /o/, /a/, /e/, /i/ using magnetic resonance image(MRI). The subject's original vowel utterances with speech intelligibility and the synthesized vowels from MR images were analyzed. The results were as follows: (1) The vowels /a/, /e/, /i/ were perceived as the same sounds of actual subject's speech, but the vowels /o/ and /u/ were perceived as /$\partial$/ and strained /u/, respectively. (2) The synthesized vowels /a/ and /e/ from the MR images were perceived as the same sounds, but the vowels /u/, /o/, /i/ were perceived as different sounds. (3) The synthesized vowel by the expanded pharyngeal segment of 3 times in vowel /o/ was perceived as more natural than that of 2 times. The pharyngeal areas with varied sizes should be experimented to secure better speech production because the correct shapes of the vocal tract lead to distinct vowel production.

• Phonetics and Speech Sciences
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• v.3 no.1
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• pp.135-143
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• 2011

This study evaluated the respiratory capacity of spastic cerebral palsy children who were grouped by GMFCS (Gross Motor Function Classification System) levels and identified the acoustic characteristics of three different types of Korean stops (stop consonants) which are needed for the temporal coordination of larynx and supra-larynx, in these children. Thirty-two children with dysarthria due to spastic cerebral palsy were divided into two subgroups: 14 children classified at GMFCS levels I~III were placed in Group 1 and 18 classified at GMFCS levels IV~V were placed in Group 11, and 18 children with normal speech were selected and placed in the control group. /a/ pronged phonation (sustained vowel /a/) and nine Korean VCV syllables were used. Examined acoustic characteristics were maximum phonation time (MPT) and closure duration and aspiration duration. The results were as follows: 1) The MPTs of the cerebral palsy (CP) groups, both Group I and Group II, were significantly shorter than those of the normal group. 2) The closure durations of the two CP groups were longer than those of the normal group for all 9 target syllables. 3) The aspiration durations of the two CP groups were longer than those of the normal group. 4) The closure duration of the normal and CP Group I was significantly different among tense, aspirated, and lax. However, the CP Group II was different from normal. 5) The aspiration duration of the normal and CP Group I was significantly different among aspirated, tense, and lax. However, the CP Group II was different from normal. 6) The place of articulation influenced less than the manner of articulation on closure and aspiration duration.

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

• MALSORI
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• no.52
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• pp.49-60
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• 2004

The purpose of this paper was to evaluate the effect of hearing level on fundamental frequencies in children. Participants totaled sixty children divided by three groups: congenitally deafened children with cochlear implantation(CI), congenitally deafened children with hearing aids(HA), and children with normal hearing(NH). Fundamental frequencies were measured during the sustained phonation of a vowel /a/. There was statistically significant difference of fundamental frequencies across the groups(p<.01). In post hoc analysis, HA and NH group showed statistically significant difference, but CI group didn't showed significant differences with two groups. In correlation analysis between F0 and the chronological age, there were significant negative tendencies in CI and NH group, but not in HA group. The characteristics of fundamental frequency in CI group were found similar to NH group than HA group in this study. Therefore the results of this study suggest that the hearing level is one of the influencing factors to the fundamental frequency of children.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.65-74
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• 2020

This study aims to compare the acoustic characteristics of vowel phonation in children with spastic and dyskinetic cerebral palsy (CP). Thirty-four children aged 4-12 years with CP participated in the study (spastic 26, dyskinetic 8). Voice samples for the acoustic analysis were extracted from a sustained vowel /a/. All acoustic measures were made using Praat. Group differences were compared by an independent t-test or Welch-Aspin test, if the equivalence assumption was not met. The results of this study are as follow. First, maximum phonation time(MPT) was significantly shorter for the dyskinetic CP than for the spastic CP. Second, shimmer percent was significantly increased in the dyskinetic CP than in the spastic CP. Lastly, there were no significant group differences in both the first formant and the second formant. These findings indicate that the dyskinetic CP has a poorer respiratory capacity and poorer laryngeal function than the spastic CP. On the other hand, both groups have a comparable ability to articulate the vowel /a/. The results of the present study help speech language pathologists identify the speech motor control ability of children with two types of CP (spastic and dyskinetic) and help to make an intervention plan associated with a specific type of CP.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.15 no.2
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• pp.133-140
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• 2004

Background and Objectives : Vowels and resonant including nasals and liquid are produced with vocal folds vibration have been used for voice therapy of hyperadduction patients. This study was conducted to investigate phonatory characteristics of vowels and resonant consonants through the EGG measures from Lx. Speech studio (Laryngograph Ltd, UK). Materials and Method : 7 male adults produced sustained vowel /a/, /i/, /u/, nasals /m/, /n/, /${\eta}$/and liquid /I/ and read the sentences (1nasals-liquid sentence, 1 non-nasals-liquid sentence) and tongue-tip trill and humming. Fx(Hz), Ox(%) were obtained of vowels, nasals, liquid and each of the posterior vowel /a/ of /ma/, /na/, /la/, /ha/ with same F0(around F#165Hz) and amplitude (75${\pm}$5db). And also DFx(Hz), DQx(%), CFx(%) and CAx(%) were obtained from reading two kinds of sentences. Results : Qx(%) was the highest in /u/ of vowels, and nasal/n/ of the resonant consonants and nasals-liquid sentence was higher Qx than non-nasals-liquid sentence but significant differences were not found. Qx(%) of the posterior vowel /a/ of nasal consonants/n/ was higher than in the isolated vowel/a/ and other posterior vowel of resonant consonants and fricatives /h/. Regularity or periodicity and higher Qx were observed in the nasals-liquid sentence than non-nasals-liquid sentence in graphs of QxFx & CFx produced by Quantiative analysis. In the nasalance score, /u/vowel was significant higher among the vowels and /I/ liquid was significant lower among the resonant consonants and nasals-liquid sentence is higher than non-nasals -liquid sentence. CQ(%) was not significantly correlated with nasalance(%). Conclusion : These findings might signify resonant phonation was not correlated with nasalance.

• Speech Sciences
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• v.10 no.3
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• pp.7-27
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• 2003

Esophageal Speech uses the esophageal air during phonation. Fluent esophageal speakers frequently intake air in oral communication, but unskilled esophageal speakers are difficult with swallowing lots of air. The purpose of this study was to investigate the difference of acoustic characteristics of vowel and consonants production according to the speech proficiency level in esophageal speech. 13 normal male speakers and 13 male esophageal speakers (5 unskilled esophageal speakers, 8 skilled esophageal speakers) with age ranging from 50 to 70 years old. The stimuli were sustained /a/ vowel and 36 meaningless two syllable words. Used vowel is /a/ and consonants were 18 : /k, n, t, m, p, s, c, $C^{h},\;k^{h},\;t^{h},\;p^{h}$, h, I, k', t', p', s', c'/. Fundermental frequency (Fx), Jitter, shimmer, HNR, MPT were measured with by electroglottography using Lx speech studio (Laryngograph Ltd, London, UK). 36 meaningless words produced by esophageal speakers were presented to 3 speech-language pathologists who phonetically transcribed their responses. Fx, Jitter, HNR parameters is significant different between skilled esophageal speakers and unskilled esophageal speakers (P<.05). Considering manner of articulation, ANOVA showed that differences in two esophageal speech groups on speech proficiency were significant; Glide had the highest number of confusion with the other phoneme class, affricates are the most intelligible in the unskilled esophageal speech group, whereas in the skilled esophageal speech group fricatives resulted highest number of confusions, nasals are the most intelligible. In the place of articulation, glottal /h/ is the highest confusion consonant in both groups. Bilabials are the most intelligible in the skilled esophageal speech, velars are the most intelligible in the unskilled esophageal speech. In the structure of syllable, 'CV+V' is more confusion in the skilled esophageal group, unskilled esophageal speech group has similar confusion in both structures. In unskilled esophageal speech, significantly different Fx, Jitter, HNR acoustic parameters of vowel and the highest confusions of Liquid, Nasals consonants could be attributed to unstable, improper contact of neoglottis as vibratory source and insufficiency in the phonatory air supply, and higher motoric demand of remaining articulation due to morphological characteristics of vocal tract after laryngectomy.