Split case marking and prominence relations
This dissertation is concerned with split-ergative and related systems in which multiple case marking patterns are found within a single language. The central goal of the dissertation is to investigate the conditions under which different cases are assigned, and the relationship between case-assignment and the structural positions of arguments. This investigation is carried out within a version of Principles and Parameters Theory.
Central to my argument is the idea that NP arguments possess features which determine their discourse prominence. These features include lexico-semantic features such as definiteness, animacy, and person, and morphosyntactic features related to aspectual interpretation. Ideally, the mapping of arguments onto argument positions should ensure that the structural prominence of NP arguments accurately reflects nonstructural notions of prominence. This, however, is not always possible since difference notions of prominence will not always coincide.
I argue that the fundamental difference between structural and lexical (inherent) case lies in the types of NPs which they are capable of licensing. Lexical case is capable of licensing a wider range of NPs than structural case. Structural case will always be capable of licensing NPs whose prominence is accurately reflected in structure. However, in many languages structural case will be insufficient to license arguments whose prominence conflicts with their structural position. In such instances, lexical case must be employed. Split case marking systems arise in precisely those cases where a language is sensitive to prominence conflicts of a particular kind.
I also argue that structural prominence must be construed as a relational notion rather than an absolute one. NPs achieve structural prominence or nonprominence by virtue of their relation to another NP. A consequence of this is that the subject of an intransitive verb will be treated as neither prominent nor nonprominent. As a result, split case marking will often cause transitive clauses to behave differently from intransitive ones, resulting in ergative marking. In languages where ergative case can be assigned to intransitive subjects, features of the verb may enter into prominence relations with NPs, providing an account for active case marking systems.