This thesis focuses on the activity of non-professional interpreting realised in multilingual institutional contexts by bilingual speakers who perform it spontaneously and in an ad-hoc way (“natural translation”, Harris, 1977; Müller, 1989). Adopting a Conversation Analytical (CA) framework, the author focuses on turn-taking and on the mechanisms and resources by which participants coordinate their talk during the activity of oral translation. Research focusing on interpreting inspired by interactional approaches (see “dialogue interpreting”, Wadensjö, 1998; Mason, 1999; Bolden, 2000; Davidson, 2000; Gavioli, 2009; Baraldi & Gavioli, 2012) has highlighted that face-to-face interaction mediated by an interpreter constitutes a specific speech exchange system and that the presence of an interpreter modifies the participatory configuration of the encounter and the sequential order of talk. These studies focus especially on the distribution of turns (the “turn-allocational” component) and less (but see e.g. Apfelbaum, 2004) on the way these turns are formatted from a syntactic, prosodic, semantic, pragmatic and multimodal point of view (the “turn-constructional” component), i.e. how they project and make recognizable a place where transfer of speakership is relevant and possible (Sacks et al., 1974; Couper-Kuhlen & Selting, 1996; Ford et al., 1996; Auer, 2002; Mondada, 2007).