Public spending reductions across the advanced capitalist world are creating new professions that have a "hybrid" status and/or role. However, research on professional learning has paid little attention to them. This qualitative study of one such profession, public service interpreting (PSI), addresses that lacuna. The paper focuses on interpreters' interactions with other professionals and with migrants using public services. It evokes Bourdieu's important but neglected concept of "illusio"--the extent to which players invest commitment in the stakes of a field--to frame the analysis. This highlights the lack of autonomy for PSI, interpreters' own ambiguous "illusio," and their conflicts with the illusio of more powerful professions with which they must work. We conclude that there is a need for more research on the power relations between new hybrid professions and established professions, and that Bourdieu's "illusio" is a potent analytical concept for this task.