A formal functional model of tone

Formalist and functionalist approaches to language have long been seen as inherently antagonistic, but in recent years this has begun to change, as formalists recognize the influence of language use on linguistic structure, and functionalists provide more explicit models for how this influence operates. The model of tone proposed here is formal in the sense of aiming to provide a completely explicit account of phonological knowledge, yet it is also functionalist, since its elements take the form they do because of the way phonological knowledge is actually used when speaking, hearing, and acquiring a language. In particular, this paper builds on the tonal insights of Tsay (1994) and the functional Optimality Theory formalism of Boersma (1998) to propose a new model that explains important aspects of tonal behavior: limits on the number of level tones, interactions of tones and other features, and tone spreading. Data primarily come from tone languages of the Sino-Tibetan family