This article considers a case of local language socialization and accommodation in a multilingual community of practice: the use of English as an additional academic language for specific purposes at a bilingual Swiss university and its implications for teaching. The acronym ELF(A) is used throughout as short for English as a Lingua Franca (in Academic settings). The bilingual university's multilingual habitat also shapes the kind of ELF(A) used and this has in turn informed the teaching of English for Plurilingual Academic Purposes (EPAP). The discussion draws on both ethnographic research carried out in multilingual disciplinary speech events and on the author's simultaneous and continuing experience of developing and teaching English for academic purposes (EAP). It focuses on an oral presentation to a life science journal club made by a multilingual doctoral student socialized into the use of English almost exclusively in the ELF(A) habitat. Using the plurilingual repertoire to sustain "code-sharing" lingua franca mode, one of the habitat's most striking effects is the effort users are willing to expend in striving for autonomous functionality in their Englishes without overt switching, while simultaneously relying on their audience's multilingual flexibility and shared disciplinary knowledge, e.g. in the pronunciation of technical terminology. The habitat of a multilingual community of practice that assumes responsibility for its novices' language socialization in an additional medium is thus a supportive factor empowering junior scientists to function in English. To the extent that the habitat factor contains a limiting dimension of context dependence, however, teaching EPAP should also target speakers' (potential) needs for spoken academic language use elsewhere.