Functional Discourse Grammar (FDG), as a theory of the organization of natural languages, seeks to attain pragmatic, typological and cognitive adequacy. The attempt to achieve cognitive adequacy has been fraught with problems stemming from the vagueness of the concept and the difficulty of adapting to trends in psycholinguistics. Specifically, while FDG has seen every utterance as an entirely novel creation by an individual language user, developments in cognitive science have emphasized the extent to which aspects of utterances are primed by earlier occurrences in the context of dialogue involving two or more interlocutors. It is possible to develop a dialogic view of FDG in which the Contextual Component is re-interpreted as an implicit common ground and as a conduit for the interactive alignment of grammatical processes. In such a view, morphosyntactic alternations are defined by their potential for mutual priming. The analysis of dialogue data shows that authentic linguistic expressions, examined in their discourse context, can be described as being determined either by priming or by functional factors, with several instances of dysfunctionality being attributed to the influence of priming. (Contains 2 figures and 1 table.)