This paper, based on examination of initial F0 of bilabial stops in Standard Thai, reports that pre-voiced bilabial stops (negative VOT) have lower initial F0 than the voiceless (approximately 0ms VOT) or voiceless aspirated stops (those with positive VOT). Also reported in this paper are measurements from electromyographic (EMG) laryngeal muscle activity (cricothyroid and strap muscles) associated with the initial F0 of the bilabial stops. The F0 and EMG data are discussed in terms of historical theories of tonogenesis for Thai. The F0 data support the hypothesis of tonogenesis as put forth by historical linguists; however, a connection between the laryngeal muscles examined and the high/low intrinsic F0 of the bilabial stops was not found. Additional acoustic, aerodynamic and laryngeal research is needed in order to understand the interaction between initial stops and the development of tones.
Erickson et al. (Sun,) studied this question.