How Gaps and substitutions can become optimal: the pronominal affix paradigms of Yimas

Abstract

In order to describe the possible and impossible pronominal prefix combinations in the Yimas verb, a set of partially ordered constraints is proposed within the correspondence format of Optimality Theory (OT). These constraints simultaneously explain the split in the inventory, the order of prefixes, why gaps appear in some category combinations, and why less specified prefixes substitute for fully specified ones in other combinations. Moreover, I will show that the Yimas inventory of ergative and accusative morphemes is rather stabile under the given constraint ranking. A scenario in which Yimas shifts to a pure accusative system is more imaginable than a scenario in which it shifts to a pure ergative system, despite the fact that the ergative morphemes outnumber the accusative ones. Thus, an OT account may result in evaluations of the inventory that differ from more intuitive judgments.