Effect of the Nasal Cavity Resonance on the Acoustic Characteristics of Korean Vowels

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J Korean Soc Laryngol Phoniatr Logop > Volume 4(1); 1991 > Article

Journal of The Korean Society of Laryngology, Phoniatrics and Logopedics 1991;4(1): 24-32.

비강 공명이 한국어 모음에 미치는 음향학적 영향

성명훈, 오승하, 강명구, 고태용, 김광현, 김진영

서울대학교 의과대학 이비인후과학교실

Effect of the Nasal Cavity Resonance on the Acoustic Characteristics of Korean Vowels

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ABSTRACT

Cleft palate or velopharyngeal incompetence shows many disorders and disabilities affecting speech transmission. including distortion. substitution. and the nasalization of the vowels. The nasalized vowels are produced primarily by lowering of the velum. resulting in opening a side passage for the air flow through the nasal cavity. These abnormal movements give rise to complex modification of the physical property of the sound or in the sound spectrum. The authors employed Sonagraph$^{circledR}$ as a sound analyzer in order to ascertain the features which characterize the nasalization of vowels. Twenty healthy Korean male adult voluteers were analyzed in artificial conditions of anterior and posterior nasal obstruction. and velo-pharyngeal incompetence. The results were as follows : 1) Fundamental frequency was not changed by nasal obstruction or velopharyngeal incompetence. 2) There was no significant difference of the formant intensity between normal and nasal vowels. 3) In VPI, a decrease of the frequency of $F_2$ was observed in /e/ and /i/ vowels(p<0.001). 4) In VPI, the $F_2$ was frequently missed in /o/ and /u/ vowels. 5) In the consonant spectra of VPI, the 'release burst' was usually not observed.