In this dissertation I provide an account of the distribution of Korean clause-typing markers from the perspective of a formal typological model, the Universal Spine Hypothesis (Wiltschko, 2014, 2017). Although Korean clause-typing markers have both syntactic properties (expressing force/mood, Chomsky 2000, 2001) and pragmatic properties (expressing speech styles, Sohn 1999), my investigation focuses on the morphosyntactic properties of clause-typing markers in single-layered and double-layered CPs. I detail their ability to transmit clause type, their compatibility with TAM elements, and their incompatibility with subordinators and speech act elements. My central claim is that, through an association with the linking spine (i.e., CP in generative grammar), clause-typing markers, including ta and e, construct Korean language-specific categories. Clause-typing markers interact with a syntactic domain encoding the common ground of speech participants, the grounding spine. My dissertation has two major findings. First, the morphophonological realization of C is obligatory in both finite and non-finite clauses. I therefore propose a Clause Complementation Parameter (CCP)—all clauses must have a complementizer, and a C must have a correspondent PF realization. This accounts for the expletive-like dummy complementizers e and ci which can fill the head of the three basic clause types. Second, functional elements selecting clause-typing markers support the existence of syntactic projections above the traditional CP. For instance, iterative ko and hearsay y in reiterated and hearsay utterances, respectively, must be associated with the syntactic domain above CP. I argue that along with polite yo and intonation, they construct Korean language-specific categories through their association with the three universal categorizers k: linking, k: grounding, and k: responding. This is formulated as [RespP [GroundP [LinkingP [AnchoringP …-ssPAST] -taDECL] -yHEARSAY] (-yoPOLITE) -↑]. Investigations of the distributions of periphrastic irrealis clause-typing markers and multifunctional clause-typing markers contribute to our understanding of the multifaceted nature of category C: the periphrastic irrealis markers show that C with T can restrict the person feature on the subject. The interpretations of multifunctional markers in different morphosyntactic contexts show that their properties emerge in two ways: through interaction with local elements in the domain or by virtue of their association with hierarchically distinct domains. Assuming the Universal Spine Hypothesis, I have accounted for the morphosyntactic properties of Korean clause-typing markers by proposing language-specific categories considering the functional layers. This dissertation offers a more complete account of Korean grammar but also will provide an explanation for cross-linguistic differences in encoding of clause-typing—Units of Languages change how C appears. / Graduate