On fluid differential case marking: A bidirectional OT approach

We will provide a bidirectional Optimality Theoretic approach for fluid differential case marking, in particular fluid differential subject marking. Our claim is that although there is no fixed meaning associated with any particular type of case, a correspondence constraint between volitional meaning and ergative case interacts with markedness constraints and this interaction may result in fluid differential case marking. Thus, fluid differential subject marking is analysed as the emergence of the correspondence between volitional meaning and ergative case in a bidirectional process of optimization. We will argue that this type of differential case marking cannot be adequately explained in unidirectional OT syntax. In a bidirectional perspective, however, fluid differential case marking can be analysed on the basis of the same set of ranked constraints that accounts for the general pattern of case marking.