This paper approaches the notion of participation in dialogue interpreting from both a theoretical and an empirical perspective. In a review of several analytical proposals for the distinction of speaker and hearer roles, it sketches a multi-level framework based on the distinction between the utterance level and the communicative-event level with interpreting as a role sui generis. Following this broad conceptual analysis, the analytical distinctions are applied to extracts of authentic discourse data from case studies in clinical and legal settings, highlighting the ways in which both untrained and court-certified interpreters may disable the primary interlocutors’ participation by their own active participation in interaction.