Exceptionality in Assamese vowel harmony: A phonological account

The complex pattern of exceptionality in Assamese vowel harmony is taken to be one of the strong empirical arguments for an OT-system with lexically indexed constraints that are locally restricted (e.g. Mahanta 2008; 2012; Pater 2010). In contrast, we argue that the two exceptionality patterns in Assamese are not an argument for the assumption of lexically indexed constraints but instead fall out as an epiphenomenon from well-known mechanisms of phonology. We present two possible purely phonological reanalyses, each assuming a different vowel feature system: One based on floating features and constraint ganging and another based on floating features and underspecification. These phonological reanalyses have important consequences not only for the argument of a strictly modular phonology that disallows any reference to morpho-syntactic features (e.g. Bermúdez-Otero 2012; Bye & Svenonius 2012), they also shed new light on the possible different sources of apparent exceptionality. More concretely, both reanalyses take the exceptional trigger for vowel harmony to be a standard instance of an unassociated feature that needs to dock to a host. An additional exceptional undergoer for another vowel harmony process receives two different interpretations that depend on the assumed vowel feature system: It is either predicted from simple underspecification that makes vowels without contrasting counterparts more prone to phonological changes or it is interpreted as a phonologically Derived Environment Effects that easily falls out from constraint ganging in Harmonic Grammar (Legendre et al. 1990; Smolensky & Legendre 2006; Potts et al. 2010).