Voice Onset Time in English Voiceless Initial Stops in Long Read and Spontaneous Monologue Speech of Thai Students with English as a Second Language

Proximity of L1 and L2 VOT (Voice Onset Time) values illustrates that L1 stop categories are used to acquire L2 ones. While a number of studies have found that VOT is very sensitive to many factors, how speech time and VOT correlate is still understudied. This study tests whether L1 transfer in terms of VOT would enhance as speech time elapses. Six university students with Thai as L1 and English as L2 were selected to produce long spontaneous monologue speech and long read monologue speech produced. VOT values in English initial voiceless stops were then segmented and analysed using the mix-effects model. The result reveals that raw VOT in spontaneous speech is significantly shorter than in read speech and no correlation between adjusted VOT and elapsed speech time is found. does not correlate with elapsed speech time. Implications of the result are discussed in terms of stylistic variation and second language acquisition.