Speaking rate and language-specific voice onset time effects on burst amplitude: Cross-linguistic observations and implications for sound change

Abstract

The relationship between speaking rate and burst amplitude in voiceless plosives was investigated in two languages with differing oro-laryngeal timing implementations of phonological voicing, North American English and Indian Tamil. Burst amplitude (reflecting both intraoral pressure and flow geometry of the oral channel) was hypothesized to decrease in CV syllables with increasing speaking rate, which imposes temporal constraints on both intraoral pressure buildup behind the oral occlusion as well as respiratory air flow. Increased speaking rate led to decreased burst amplitude (relative to vowel amplitude) in both languages, with the magnitude of the effect being considerably weaker in Tamil, which has short-lag implementation of voice onset time. Bilabials in both languages were affected disproportionately relative to other places of articulation. Additionally, burst amplitudes were lower overall in Tamil, reflecting lower intraoral pressure which promotes faster vocalic onset. Results are discussed in terms of language-internaland extra-linguistic phonetic phenomena potentially serving as perceptual triggers for historical sound change.