Japanese employs different strategies for expressing relative clauses and complement clauses. The relative clause constructions are generally described as Externally Headed Relative Clauses (EHRCs), which are the closest analogue to English relative clauses, and Headless Relative Clauses (HRCs) (also called Internally Headed Relative Clauses) which have no analogue in English. The Complement Clauses (COMPCs) constructions all involve an embedded clause followed by either an abstract nominal such as "koto" or the particle "no". There is also the "no da" construction, which, like the HRC construction, has no analogue in English. There is disagreement in the literature as to the syntax, semantics, and pragmatics of these clausal constructions. Additionally, the status and use of the particle "no" across the different constructions it occurs in is highly contentious. This study examines the nature of these clausal constructions and demonstrates that they are all nominalizations, and that the particle "no" is a nominalization marker that is required when the fact of nominalization is ambiguous. It also argues that the underlying semantics of "koto" and "mono", and the fact of nominalization marked by no, account for their pragmatic differences, and align with the notions of experiential judgements, which are based on a speaker's analysis of a given event, and perceptual judgements, which lack the speaker's analysis and instead present the event as directly witnessed by the speaker. Specifically, "koto" COMPCs align with experiential judgement, while "no" COMPCs and the "no da" construction align with perceptual judgement. [The dissertation citations contained here are published with the permission of ProQuest LLC. Further reproduction is prohibited without permission. Copies of dissertations may be obtained by Telephone (800) 1-800-521-0600. Web page: http://www.proquest.com/en-US/products/dissertations/individuals.shtml.]