Learning Phonology With Substantive Bias: An Experimental and Computational Study of Velar Palatalization

TLDR

Phonology debates whether substantive phonetic factors such as ease of articulation and perceptual distinctiveness are cognitively relevant. The study proposes a framework in which substantive phonetic factors act as a bias on phonological learning. The authors tested this framework with experiments in which participants received limited evidence of a new phonological pattern and were then assessed on its extension to novel contexts, using a psychological categorization model and a conditional random field to quantify perceptual similarity. Participants generalized velar palatalization from a mid front vowel to a high front vowel in line with typological patterns and perceptual similarity bias, but not in the reverse direction, supporting the substantive bias framework.

Abstract

There is an active debate within the field of phonology concerning the cognitive status of substantive phonetic factors such as ease of articulation and perceptual distinctiveness. A new framework is proposed in which substance acts as a bias, or prior, on phonological learning. Two experiments tested this framework with a method in which participants are first provided highly impoverished evidence of a new phonological pattern, and then tested on how they extend this pattern to novel contexts and novel sounds. Participants were found to generalize velar palatalization (e.g., the change from [k] as in keep to [t?∫S] as in cheap) in a way that accords with linguistic typology, and that is predicted by a cognitive bias in favor of changes that relate perceptually similar sounds. Velar palatalization was extended from the mid front vowel context (i.e., before [e] as in cape) to the high front vowel context (i.e., before [i] as in keep), but not vice versa. The key explanatory notion of perceptual similarity is quantified with a psychological model of categorization, and the substantively biased framework is formalized as a conditional random field. Implications of these results for the debate on substance, theories of phonological generalization, and the formalization of similarity are discussed.