Contrast implementation affects phonetic variability: A case study of Hindi and English stops

There is a large body of work in phonetics and phonology demonstrating sources and structure of acoustic variability, showing that variability in speech production is not random. This paper examines the question of how variability itself varies across languages and speakers, arguing that differences in extent of variability are also systematic. A classic hypothesis from Dispersion Theory (Lindblom, 1986) posits a relationship between extent of variability and phoneme inventory size, but this has been shown to be inadequate for predicting differences in phonetic variability. I propose an alternative hypothesis, Contrast-Dependent Variation, which considers cue weight of individual phonetic dimensions rather than size of phonemic inventories. This is applied to a case study of Hindi and American English stops and correctly predicts more variability in English stop closure voicing relative to Hindi, but similar amounts of lag time variability in both languages. In addition to these group-level between- language differences, the results demonstrate how patterns of individual speaker differences are language-specific and conditioned by differences in phonological contrast implementation.