Grammaticalization of modal markers has long been thought of in terms of change from deontic to epistemic meaning. This change, then, is typically thought of as a mapping between conceptual domains. Contrary to this perception, it is argued in this paper that (1) change from deontic to epistemic (that is, the acquisition of epistemic meaning by deontic markers), although salient in many European languages, is cross-linguistically a marginal tendency, (2), the cross-linguistically most salient tendency in the development of modal markers is towards greater speaker-orientation, and (3), this change can best be explained by primarily referring to pragmatic processes, rather than conceptual processes. These claims are substantiated by analyzing the cross-linguistic modality data in Bybee et al. (1994), by providing a catalogue of etymologies of Modern Japanese modal markers, and by analyzing the polysemy and semantic change of one specific marker in Japanese language history (-be-si) in detail.