Dissertation Title: Epistemic Modality and Evidentiality in Gitksan at the Semantics-Pragmatics Interface

Abstract: The aim of this dissertation is to provide an empirically driven, theoretically informed investigation of how speakers of Gitksan, a Tsimshianic language spoken in the northwest coast of Canada, express modal and evidential meanings. In addition to documenting the morphemes in Gitksan that encode these meanings, I work through a variety of theoretical tools from the literature designed to investigate the semantics of evidentiality and modality. This begins by determining what level of meaning the individual evidentials in Gitksan operate on. The current state of research into the connection between evidentiality and epistemic modality has identified two different types of evidentials defined by the level of meaning they operate on: propositional and illocutionary evidentials. These two types correspond to a distinction between modal evidentials and non-modal evidentials respectively. I show that Gitksan has both modal and non-modal evidentials. This leads to an analysis where the Gitksan modal evidentials are treated as a specialized type of epistemic modals, and the non-modal evidentials are sentential force specifiers.
I also identify various features of the evidential system that bring specific issues to bear upon current theories of the semantics and pragmatics of modality. This has four outcomes: first, I present a novel analysis of variable modal force in modals with fixed quantification: variable modal force in Gitksan modal evidentials is determined by the ordering source. Second, I discuss Conjectural Questions: when a modal evidential is added to a question it reduces the interrogative force of the question. This follows from the modal semantics of evidentials. Thirdly, I introduce the notion of Pragmatic Blocking: modal and non-modal evidentials interact in discourse contexts, and implicate a speaker’s attitude towards the evidence they have for a proposition. And fourth, I develop the first formal analysis of mirativity and non-literal uses of evidentials, analyzing them both as cases of conversational implicature.