VOICE ONSET TIME OF KOREAN STOPS PRODUCED BY THAI LEARNERS OF KOREAN AS A FOREIGN LANGUAGE

Abstract

This study aimed to analyze the Voice Onset Time (VOT) of Korean stop consonants produced by Thai native speakers who are learning Korean as a foreign language. The participants were three Thai native speakers, and one native Korean speaker (Seoul dialect), who served as a reference. The word list used for data collection included Korean words beginning with three types of stop consonants: aspirated, tense, and lax, produced at three places of articulation—bilabial, alveolar, and velar. In addition, Thai words containing three types of Thai stop consonants—voiceless aspirated, voiceless unaspirated, and voiced—were collected for comparison. The statistical methods used in this study were descriptive statistics, including the arithmetic mean (Mean) and standard deviation (S.D.).

The results showed that the Thai native speakers were able to produce Korean aspirated stops accurately, with VOT values close to those of the native Korean speaker. However, the lax stops at the bilabial and alveolar places of articulation displayed negative VOT values (Voicing Lead), acoustically indicating the production of a voiced stop, similar to the voiced stops in Thai. The VOT values of the lax stop consonants at the velar place of articulation varied substantially across speakers, with some producing values higher than and others lower than those of the tense stops at the same place of articulation. In contrast, the tense stops showed the shortest VOT values among all stop types and were relatively stable across all places of articulation for every speaker.