Symmetrical objects in Moro: Challenges and solutions

This paper examines the syntactic and semantic behavior of object arguments in Moro, a Kordofanian language spoken in central Sudan. In particular, we focus on multiple object constructions (ditransitives, applicatives, and causatives) and show that these objects exhibit symmetrical syntactic behavior; e.g., any object can passivize or be realized as an object marker, and all can do so simultaneously. Moreover, we demonstrate that each object can bear any of the non-agentive roles in a verb's semantic role inventory and that the resulting ambiguities are an entailment of symmetrical object constructions of the type found in Moro. Previous treatments of symmetrical languages have assumed a syntactic asymmetry between multiple objects and have developed theoretical analyses that treat symmetrical behaviors as departures from an asymmetrical basic organization of clausal syntax. We take a different approach: we develop a Head-Driven Phrase Structure Grammar account that allows a partial ordering of the argument structure (ARG-ST) list. The guiding idea is that languages differ with respect to the organization of their ARG-ST lists and their consequences for grammatical function realization: there is no privileged encoding, but there is large variation within the parameters defined by ARG-ST organization. This accounts directly for the symmetrical behaviors of multiple objects. We also show how this approach can be extended to account for certain asymmetrical behaviors in Moro.