The perceptual acquisition of Thai phonology by English speakers: task and stimulus effects

Abstract

This article presents a follow-up to Curtin et al.’s study of the perceptual acquisition of Thai laryngeal contrasts by native speakers of English, which found that subjects performed better on contrasts in voice than aspiration. This finding - surprising in light of earlier cross-linguistic voice onset time (VOT) research - was attributed to the fact that the task tapped lexical representations, which are unspecified for aspiration according to standard assumptions in generative phonology. The present study further investigated possible task effects by examining the discrimination and categorization of the same stimuli in various experimental conditions. Stimulus effects were also investigated by performing token-based analyses of the results, and by comparing them to acoustic properties of the tokens. The outcome of the discrimination experiment was the opposite of the earlier study, with significantly better performance on contrasts in aspiration than voice, even on a lexical task. A second finding of this experiment is that place of articulation interacts with the perception of the laryngeal distinctions; the aspiration distinction is discriminated better on the labials, and voice on alveolars. A parallel effect of place of articulation was also found in a categorization experiment.