Phoneme Similarity and Confusability

Similarity between component speech sounds influences language processing in numerous ways. Explanation and detailed prediction of linguistic performance consequently requires an understanding of these basic similarities. The research reported in this paper contrasts two broad classes of approach to the issue of phoneme similarity-theoretically driven measures based on phonological features, and empirically derived measures based on confusability. Two experiments are used to test a variety of measures from both classes for their ability to predict judgments of similarity between English consonants. The simplest featural measure is the best on these tests. This recommends it as the basis for further explorations, and improvements to the basic feature model are identified. The paper concludes by examining the extent to which confusability depends on phoneme similarity.