This proposed European research network will stand at the crossroads between language, social interaction, cognition, and the human brain. We believe that now is an appropriate moment for this network to arise, and that Europe offers a framework that will allow us to establish new collaborations to engage ourselves in very exciting scientific challenges. There is an extensive tradition of research on the relationships between language and the brain, but work in this domain has long been restricted to studying language production and comprehension in single individuals, using highly-controlled linguistic material. However, thanks to recent theoretical, methodological and empirical advances in language sciences, cognitive sciences and neurosciences, we are now in a position to extend our studies to ensembles of speakers engaged in conversational interactions. Our research now increasingly focuses on language in its primary site of occurrence, that is social interactions between people, and on how these interactions may both rely on and contribute to setting up brain-to-brain coupling relationships. We believe that a major turning point has been reached, in that social interactions between people are now the most appropriate framework for studying language and its cerebral and cognitive underpinnings.