Abstract
I will review some recent work in collaboration with Ewan Dunbar and Brian Dillon on the use of unsupervised clustering techniques to discover vowel categories. The novel and important point of this work is to try to discover categories with predictable variants, i.e. phonemes with their related allophones. We achieve this by finding categories and transforms on the categories rather than first finding a larger set of more detailed categories (phones) and then later grouping the induced categories into more abstract categories (phonemes). A similar approach can be used to cluster “higher-order invariants” for consonants, in this case locus equations. Finally, we will examine some of the implications of this work for other problems in phonology such as speaker variation and incomplete neutralization.