Though a popular and somewhat controversial topic in discussions on language in IB, the notion of English as a (business) lingua franca/(B)ELF still lacks clear conceptualisation. This paper argues that research in IB and linguistics can be mutually complementary and supportive in conceptualising BELF, and that it is important to separate the concept of BELF from that of a common corporate language. The paper synthesises key works from both disciplines to conceptualise BELF as an emergent, multilingual use of English that adapts to the demands and resources of the specific context. It further argues that Wenger's (1998) concept of Communities of Practice offers a useful bridge between the disciplines, and that there is a need for more empirical research.