Vowel Duration as a Perceptual Cue for Preceding Stop Laryngeal Contrast in Korean

This study explores the effects of vowel duration in identifying the previous stop laryngeal contrast in Korean. The durational resolution in Korean shows a limited variation of syllable duration and a strong correlation between VOT and vowel duration [1]. The systematic variation of vowel duration due to different VOTs of prevocalic stops suggests vowel duration as a plausible perceptual cue in identifying the preceding stops. Identification tests on stop categories (plain, tense, aspirated) in Korean were conducted with 12 native Korean listeners, using 33 disyllabic word tokens in the utterance-initial position. All sound tokens were manipulated in the vowel duration, pitch, and VOT. The results show that listeners employ multiple cues of VOT, pitch, and vowel duration in identifying the stop categories. It is also confirmed that vowel duration is actively used, even with unambiguous F0. The effect of vowel duration, however, is found to depend on stop laryngeal categories. Identification of the plain stop based strongly on F0 information. The effects of vowel duration were more obvious in tense and aspirated stops in the higher F0 ranges.