Voice Onset Time(VOT) During Korean Plosives Production : A Preliminary Study on Normal and Apraxia of Speech Subjects

한국어 파열음상의 Voice Onset Time(VOT) : 정상군과 언어실행증 환자비교에 대한 사전 연구

Aberrations in VOT measures in apraxia of speech are indicative of speech motor programming impairment. In English, overlaps of VOT between voiceless and voiced plosives have been frequently observed in patients with apraxia of speech. Unlike English, Korean plosives constitute trichotomy in terms of manner of production, that is, voiceless aspirated /p', t', k'/ ; voiceless or voiced, weakly aspirated /p-b, t-k, k-g/ ; or voiceless, heavily aspirated /p, t, k/. In this spectrographic study, VOT measures during Korean plosives produced by a patient with apraxia of speech were compared to those by age- and gender- matching normal subjects. The results indicated that there were partial overlaps between VOT of /b, d, g/ and those of /p, t, k/, implying that the errors were phonetic in nature. In addition, larger VOT variabilities in apraxia of speech compared to the normals were noted.