This study deals with interactional processes in conversational discourse, and the way they may get 'syntacticized' into grammatical constructions. It investigates the link between discourse function and syntactic form, and the ways in which grammatical form is a reflection on communicative function, through examining the communicative functions of Left-Dislocation in English. The investigation is corpus-based, and focuses on spontaneous conversation, but other discourse types are also taken into account. The overall perspective is resolutely empirical, and preconceptions about the possible functions of Left-Dislocation are avoided.