The authors, an applied linguist and an academic lawyer, describe how they collaboratively problematise and co-develop conceptual learning materials for finance professionals enrolled in a postgraduate study unit called Legal Risk in Finance. Activities are designed to function as "boundary objects" bridging the gap between two professional visions. These "objects" are intended to help the finance professionals engage for the first time with categories of meaning and discursive practices that are often represented in terms superficially similar to those of their own professional domain. The authors also document their own cross-disciplinary collaboration, which takes place in sites of engagement that together constitute a "back region" relative to the classroom's "front region" (Goffman 1959). In this "second site" the applied linguist qua discourse analyst identifies areas of conceptual difficulty and potential misunderstanding. There have been numerous studies of professional acculturation and socialisation, especially in the medical and legal domains; but as yet little in the realms of finance and finance law. Moreover, the classroom is rarely seen as the site of such processes. Yet for many postgraduate students that is precisely where they first confront the categories of a new professional domain. The role of applied linguists in tertiary curriculum development is another neglected research topic involving cross-boundary professional partnerships.