• Maxillofacial Plastic and Reconstructive Surgery
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• v.23 no.1
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• pp.48-58
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• 2001

After performing mandibular setback surgery, we found some changes in patterns and organs of speech. This investigation was undertaken to investigate the aspect and degree of speech patterns according to the amount of surgical setback in mandibular prognathic patients. Thirteen patients with skeletal Class III malocclusion were studied preoperative and postoperative over 6 months. They had undergone the mandible setback operation via bilateral sagittal split ramus osteotomy(BSSRO). We split the patients into two groups. Group 1 included patients whose degree of mandibular setback was 6mm or less, and Group 2 above 6mm. Control group was two adults wish normal speech patterns. A phonetician performed narrow phonetic transcriptions of tape-recorded words and sentences produced by each of the patients and the acoustic characteristics of the plosives, fricatives, and flaps were analyzed with a phonetic computer program (Computerized Speech Lab(CSL) Model 4300B(USA)). The results are as follows: 1. Generally, Patients showed longer closure duration of plosives, shorter VOT(voice onset time) and higher ratio of closure duration against VOT. 2. Patients showed more frequent diffuse distribution than the control group in frication noise energy of fricatives. 3. In fricatives, frequency of compact from were higher in group 1 than in group 2. 4. Generally, a short duration of closure for /ㄹ/ was not realized in the patient's flaps. Instead, it was realized as fricatives, sonorant with a vowel-like formant structure, or trill type consonant. 5. Abnormality of the patient's articulation was reduced, but adaptation of their articulation after surgery was not perfect and the degree of adaptation was different according to the degree of surgical setback.

• Speech Sciences
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• v.9 no.1
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• pp.17-26
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• 2002

Voice onset time (VOT) is defined as the time interval from the oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristic of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. There have been many reports on efforts to clarify the acoustical and physiological properties that differentiate the three types of Korean stops, including acoustic, fiberscopic, aerodynamic and electromyographic studies. In the acoustic and fiberscopic studies for stop consonants, the voice onset time and glottal width during the production of stops has been known as the longest and largest in the heavily aspirated type followed by the slightly aspirated type and unaspirated types. The thyroarytenoid and posterior cricoarytenoid muscles were physiologically inter-correlated for differentiating these types of stops. However, a review of the English literature shows that the fine movement of the mucosal edges of the vocal folds during the production of stops has not been well documented. In recent. years, a new method for high-speed recording of laryngeal dynamics by use of a digital recording system allows us to observe with fine time resolution. The movements of the vocal fold edges were documented during the period of stop production using a fiberscopic system of high speed digital images. By observing the glottal width and the visual vibratory movements of the vocal folds before voice onset, the heavily aspirated stop was characterized as being more prominent and dynamic than the slightly aspirated and unaspirated stops.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.16 no.1
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• pp.53-67
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• 2005

It is known that Korean stop consonants in syllable-initial position are of three types : lax, aspirated and forced (or unaspirated). In syllable-final position, however, these three different types are merged to a single type with the same place of articulation, although the original three-way distinction is preserved in Korean orthographic (Hangul) system. Thus the syllable-final stops are phonetically realized as voiceless "applosives" which are characterized by the absence of oral release. The aim of the present study is to investigate the laryngeal adjustments for these syllable-final stops in various phonological conditions by using fiberscope, and, is to further investigate electromyographically the laryngeal adjustments for Korean stops both in the syllable-initial and final positions in various phonological conditions. The results can be summarized as follows : 1. In the case of syllable-initial stops, the glottal widths in each three types of the Korean stops during the articulatory closure are clearly different. And the pattern of thyroarytenoid(VOC) activity appeared to characterize the three different types of Korean stops. 2. The basic laryngeal feature of the Korean syllable-final applosives is characterized by a small degree of glottal opening which begins at or slightly after the oral closure. 3. In the case, syllable-final stop followed by the copula "ita", the syllable- final stop is pronounced as the stop consonant at the initial position of the following syllable containing the vowel[i], the underlying features of three-way distinction for the stops in the Korean orthographic(Hangul) system being manifested at the laryngeal adjustment. 4. In the case of the final applosives followed by the initial stops and fricatives, the laryngeal feature of the final applosives appears to be assimilated by that of the following consonant irrespective of the difference in the place of articulation, as far as the glottal abduction/adduction is concerned. It is clearly demonstrated in the case of syllable-initial stop that thyoarytenoid(VOC) activity is suppressed for the production of the stop consonants in question, the degree of which is slightest for the forced type and most marked for the aspirated type, while it is moderate for the lax type.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.17 no.2
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• pp.98-102
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• 2006

Background and Objectives : Voice onset time(VOT) is defined as the time interval from oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristics of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. Stop consonants are characterized by creation of a pressure difference across a complete occlusion in the vocal tract, followed by a sudden release 'burst' due to opening that occlusion. The objects of this study is to evaluate a usefulness of voice onset time in the assessment of voice disorderd patients. Subjects : Subjects were 20 adults with normal voice and with benign laryngeal disorders. Subjects with voice disorders represented the following vocal pathologies : vocal polyp, vocal nodule, Reinke's edema and unilateral vocal fold paralysis(UVFP). Control subjects were matched for age (21-40 yews old) and sex(male) with the voice disorders subjects and had normal vocal qualities with no history of voice disorders. Methods : Each voice-disordered and matched control subject read the test passages containing three types of Korean bilabial consonants. VOT measures were made for the initial $/p/p^h/\;and\;/p'/$. VOT was measured using acoustic waveform or wide band spectrogram. Results : For each voiceless stop consonants, there was a significant difference in VOT between the voice disordered and normal subjects. The mean VOTs of the lax stops in UVFP was significantly shorter than those of control subjects in the UVFP. The mean VOTs of the aspirated stops in the vocal polyp and nodule were longer than those of control subjects, but not significant. The mean VOTs of the glottalized in voice disordered groups were longer than those of control subjects, and significant statistically in the UVFP. Conclusions : VOT may be a clinically useful acoustic parameter in the assessment of voice disordered patients, especially in the unilateral vocal fold paralysis.

• Journal of the korean academy of Pediatric Dentistry
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• v.27 no.4
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• pp.517-523
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• 2000

Nasopharyngeal closure is a sphincter mechanism between the activities of the soft palate, lateral pharyngeal wall and the posterior pharyngeal wall, which divides the oral cavity and the nasal cavity. It participates in physiological activities such as swallowing, breathing and pronunciation. In case of an error in this mechanism, it is called a nasopharyngeal incompetence. The causes of this error are defects in (1) length, function, posture of the soft palate (2) depth and width of the nasopharynx, (3) activity of the posterior and lateral pharyngeal wall. The purpose of this study is to analyze the nasopharynx of cleft palate patients using lateral cephalograms and at the same time, evaluate the degree of hypernasality of each vowels to find its relationship with nasopharyngeal incompetence. The following results were obtained: 1. The length of the soft palate was markedly short than normal. 2. The adequate ratio was smaller than the normal value. 3. As the adequate ratio decreased, when articulating vowels, anatomic mVPI increased. 4. When articulating each vowels, anatomic VPI was in proportion with the degree of hypernasality. 5. The degree of hypernasality was greater in high vowels(/i/, /u/) than low vowel(/a/). From the above results, it can be concluded that in cleft palate patients, lateral cephalograms can be used effectively in diagnosing and evaluating nasopharyngeal incompetence. The anatomic structure of the nasopharynx has close relation to the degree of hypernasality.