This paper focuses on the complex derivational and inflectional morphology of Somali (East Cushitic) verbs. Somali verbs are traditionally cast in three major classes, depending on specific lexical suffixes (Saeed 1993). It is assumed that these classes must be distinguished because the relevant suffixes trigger a morphologically conditioned allomorphy. We argue against this view and claim that the allomorphic patterns targeting each class are epiphenomenal. Our analysis, couched within the theoretical framework of Government Phonology (Kaye, Lowenstamm & Vergnaud 1985, 1990) and the CV-model (Lowenstamm 1996), shows that the allomorphy in question is in fact phonologically conditioned. In particular, we establish unified representations of the two major lexical suffixes – the causative and the autobenefactive – and claim that all surface realizations of these markers result from the application of regular phonological rules. Thus, contrary to what appears at first sight, Somali displays a single verbal class whose three subclasses are phonologically (not morphologically) defined.
