Perceptual similarity as a filter on tonal variation and change

Abstract

To date, most work on diachronic tone change has involved comparison of f0 trajectories in real or apparent time, or the analysis of patterns of contextual tonal variation, to try and reason about the nature of directionality constraints on tone change. In practice, such comparisons often operate under the assumption of a linear perceptual space, wherein acoustic distance is assumed to more or less directly correlate with perceptual (dis)similarity. However, this assumption should be validated to ensure that accurate inferences regarding tone variation and change can be made.

 In this talk, we present our ongoing work into probing the perceptual space of lexical tone representations, focusing on the role of temporal information. Using data from a similarity judgment task from four tonal languages, we show that differences of the same acoustic magnitude are perceived differently depending on their location in the f0 trajectory. In general, listeners show greater sensitivity to differences at tonal offsets, consistent with hypotheses put forth in previous work. However, we also find a significant effect of linguistic experience on the structuring of the similarity space. These findings show us that tonal similarity, and hence confusability, cannot be straightforwardly inferred from linear acoustic distance. We discuss the implication of these findings for our understanding of the mechanisms underlying tonal variation and change.

About the speaker

Professor James Kirby, Institute for Phonetics and Speech Processing, Ludwig Maximilian University of Munich

James Kirby is Professor of Spoken Language Processing at the IPS in Munich and Bavarian AI Chair in Spoken Language Processing. His research centres on tone and sound change, with a focus on languages of East and Southeast Asia including Vietnamese, Khmer, Madurese, Kmhmu’, and Chru. In his current project, EVOTONE (ERC Starting Grant no. 758605), he is leading a team investigating how and why tones emerge or not in language and how tone systems change over time using detailed phonetic and perceptual studies with innovative experimental methodologies and large-scale computational analysis. James is an associate editor for Laboratory Phonology, and on the council of the International Phonetic Association.