This talk will focus on a central property of interactional uses of language, namely turn-taking, and show how this has major implications for language processing. I’ll sketch how the PI Group ‘Interactional Foundations of Language’ is exploring these issues, using insights arising from many different domains (prosody, breathing, gaze, cross-linguistic and cross-modal studies, human development) and many different methods (corpus studies, perception experiments, eyetracking, brain imaging). I’ll outline an interim model of how we think it all works, and (time-permitting) broach some implications for language typology, and ask where such a system comes from.