With the conventional assumption that language ability has to be seen as separate from language use, there is now a familiar divide between explanations of language as a system (language competence) and explanations of language use (performance).  Nonetheless, in socio-linguistics, pragmatics and historical linguistics, it has continued to be assumed that explanations of social aspects of language and  language change must make reference to how language is used in social interactions.  Moreover, since the turn of the century, psychologists and those working on core properties of language – semanticists, syntacticians, phoneticians – have increasingly been exploring different versions of  the view that language has to be seen as grounded in terms of participant interaction.  Strikingly, over the same period, there has been parallel work emerging in music theory and philosophy arguing that music is grounded in participant interaction; and there are clear points of contact between these two research directions.  To draw these research trends together, this event gathers representatives of these  groups to explore issues relating to interaction raised by their research, with the goal of  exploring the consequences of seeing both language and music as mechanisms for interaction.  Speakers include Patrick Healey (QMUL) Dale Barr (Glasgow), Robin Cooper (Gothenburg), Ruth Kempson (KCL), Martin Orwin (SOAS),  Andrew Bowie and Stergios Chatzikyriakidis (RHUL), Ian Cross and Sarah Hawkins (Cambridge), Rosanna Sornicola (Naples), Rebecca Clift (Essex), Paul Drew and John Local (York), Ronnie Cann (Edinburgh).