On the peculiar distribution of the Japanese epistemic adverb 'masaka'

This study addresses the distribution of the Japanese epistemic adverb 'masaka'. In declaratives, it must co-occur with a negated epistemic modal. It can occur in polar questions but not in 'wh'-questions. We propose that 'masaka' differs from ordinary epistemic adverbs in that it expresses the modal claim that the prejacent is certainly at the not-at-issue level, while leaving the at-issue content intact. This semantics predicts that the at-issue and not-at-issue contents contradict each other in cases where 'masaka' is not licensed. Furthermore, several remaining issues are discussed. First, negated epistemic attitude verbs such as 'omow' ‘believe’ also license 'masaka'. Second, the Japanese exclamative markers 'nante/towa' also license 'masaka'. Herein we present tentative ideas for accommodating these cases. Finally, we demonstrate that the projection properties of 'masaka's' semantic contribution as not-at-issue content is complicated.