This thesis explores how question FORCE (Rizzi 1997) is represented and licensed in Korean polar alternative questions (Korean PAQs). The syntactic properties of polar alternative questions have not been fully discussed in the literature; this work seeks to address that gap. The thesis has two main components. First, I provide an initial detailed investigation into the syntactic structure of Korean polar alternative questions (Korean PAQs), also called A-not-A questions, such as ciwu-nun ca-ni an ca-ni? ‘Is Jiwoo sleeping or not?’ I argue that Korean PAQs consist syntactically of a single clause. In this respect, Korean PAQs are distinct from both alternative questions and polar questions. The second goal of this thesis is to account for the asymmetric behaviour of complementizers in main clauses and embedded clauses. Variant complementizers occur in main clauses in Korean PAQs, while neutralized ci is the only complementizer which is licensed to appear in embedded clauses. Furthermore, Korean PAQs are incompatible with constituent questions in main clauses, but compatible with them in embedded clauses. This asymmetry is explained by appealing to the notion of a unique illocutionary question force in main clauses. In main clauses, the syntactic constituent ForceP cannot carry more than one kind of illocutionary question force: it bears either constituent question force or polar alternative question force, but not both. In contrast, since embedded clauses contain non-question (non-answer-requiring) complementizers, separate question forms do not conflict with each other in this location. Based on a wide range of empirical data from Korean, this thesis proposes to distinguish Force (‘question’) complementizers in the main clauses from Type (‘interrogative’) complementizers in embedded clauses. The novel data from Korean polar alternative questions require a major rethinking of the received view on the analysis of complementizers as expressed in Rizzi (1997). My analysis shows that the pragmatic categories of illocutionary force are highly significant for syntactic analysis in ways that have not been treated consistently in theoretical discussions of questions, in particular as regards the very distinct roles of main and embedded ‘questions’. / Graduate