English why not fragment questions: A corpus-based perspective

The expressions why not can be used as a fragment, functioning either as an anaphoric information-seeking question (e.g., Kim didn’t sleep well. Why not?) or a rhetorical question (e.g., Let’s do this. Sure, why not?). The central research questions for the uses of why not as an FQ (fragment question) concern what licenses the FQ, how we can obtain a sentential meaning from its nonsentential status, and what its syntactic structure is. Existing analyses postulate sentential sources for the FQ and apply deletion operations, as often adopted for other elliptical constructions. After a brief review of the why not FQ construction’s grammatical properties, the paper discusses challenging issues for the deletion-based sentential approaches. It then presents the results of a corpus investigation of the construction in the COCA (Corpus of Contemporary American English) and sketches an alternative, direct interpretation approach in which the semantic resolution of the why not FQ construction is achieved by discourse machinery. This non-elliptical, discourse-based approach shows that once we have a system that represents structured discourse structures, we have straightforward mapping relations from the why not FQ construction to a proper propositional meaning.