Alain Létourneau and François Cooren ed., Université de Sherbrooke / Université de Montréal,International audienceStarting from pragmatic models of communication inspired by philosophy (K.O. Apel, F. Jacques, P. Ricoeur), I approach the question of dialogue by reference to the theorization of language activity according to the linguistics of enunciative operations (A. Culioli). Expounding a system of metalinguistic representation focused on the key concepts of assertion and commitment led me to present a schematization of the discursive space of discussion, by means of an oriented graph. This topological standpoint meant that exchanges in dialogue, with its entrances and exits, could be simulated. The analysis of a debate between two econom...