Propositional aspect and the development of modal inferences in English

The alignment of deontic modality with perfective lexical aspect and epistemic modality with imperfective lexical aspect has been observed in a number of recent publications on the interface between aspect and modality (e.g., Abraham 1998, 2000, 2002, 2003). The present study considers the way in which such associations arise, considering the possibility of compositional (propositional) aspect as a determining factor, and, at the same time, proposes a solution to a question arising from an earlier study (Ziegeler 2003) in which the source context for the generation of deontic modal inferences in a recently-developing semi-modal, be supposed to, was ill-defined. The earlier data is re-examined from the perspective of generic sub-categories, and it is demonstrated that the sources of the deontic modal inferences begin to appear in a normative generic type expressing social or moral duty. Deontic modality thus emerges out of an environment in which perfective lexical aspect is already a necessary feature of the original source context.