Ryan Bochnak (University of Manchester):Optional tense? Evidence from Washo

Descriptively, Washo is a language where past tense is optional, in the sense that a past tense morpheme is not obligatory in finite clauses with past temporal reference. I argue that while the past marker in Washo can be given an analysis as a past tense, morphologically tenseless clauses are also semantically tenseless. As I show, however, reaching this conclusion is not as trivial as it might seem based on superficial morphological considerations alone. I argue against a tensed analysis of morphologically tenseless clauses (e.g., Matthewson 2006) on both empirical and theoretical grounds. I provide a new argument based on Maximize Presupposition that only becomes available because of the existence of optional tense marking in Washo. This analysis raises issues regarding the nature of optional tense marking in languages that instantiate the phenomenon, as well as tenselessness and the asymmetry between past and future reference.