In this thesis, I provide an account of differential object marking (DOM) in spoken Persian couched in the framework of Aissen (2003). In analyzing Persian indefinite patterns and their interaction with DOM in this way, I illustrate how DOM in Persian is sensitive to distinctions in definiteness that are not included in the traditional definiteness hierarchy. I argue that these distinctions concern the referential stability of the object in both current discourse contexts and in future discourse contexts. In this regard, I propose a structural distinction between partitive and epistemic specificity, which in turn has an important cross-linguistic prediction. I propose that the property of identifiability in principle also be represented in the definiteness hierarchy in which an additional distinction between strong and weak varieties of identifiability is included. Finally, I indicate how other analyses of Persian DOM that do not make reference to prominence hierarchies, but assign object marking a particular semantic denotation are problematic in the larger picture.

This thesis develops a threshold-based semantics for the Turkish indirect evidential marker that predicts unexpected discrepancies in its distribution. The marker’s behavior in interrogatives, so-called interrogative flip, is shown in turn to follow from the structure of discourse, as formulated by models that incorporate speaker commitment. I first establish that the indirect evidential marks information for which a speaker’s evidence is at best second-best, given general knowledge about the world. I then formalize this generalization in modal semantic terms and show that it explains the marker’s canonical absence in reports of well-known historical fact, as well as its optional presence in evaluative and mirative expressions. After examining the account’s predictions on the level of discourse, I discuss two corollaries: that evidential content in Turkish is not propositional, and that an at best second-best account brings to light anaphoric parallels between indirect evidentiality and the present perfect relative tense.