IsiXhosa, a Bantu language of South Africa, . features a rich system of morphologically am tonologically complex verbal inflection paradigms. This paper takes an Optimality Theoretic approach to accounting for the distribution of high tones in IsiXhosa verbal paradigms, exploring the complex interactions between the tonology and prosodic and morphological structure. The result is that all 43 of the verbal inflection paradigms listed by Claughton (1983) are generated by a single constraint hierarchy characterized by morphologically conditioned rerankings, unrankings, and reformulations. This analysis therefore makes the broader prediction that given a nonderivational, constraint-based view of grammar, morphology can extend beyond morphemes into the constraint hierarchy itself.

Many thanks to Lee Bickmore, Marek Przezdziecki, Abby Cohn, Paul Smolensky, Bruce Hayes, John Goldsmith, Kirsten Fudeman and Mark Baker for their helpful comments and suggestions on earlier versions of this paper - and especially to Phelisa Zihlangu, my native speaker consultant, for all of her assistance and patience with this project All errors are my own. Examples · are given in IsiXhosa orthography, with the exception of lengthened vowels, which are represented in this paper as orthographically doubled for the sake of clarity. This working paper is copyrighted, and is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0) - see https://creativecommons.org/licenses/by-nc-nd/4.0/