The development of pedagogies to meet the needs of diverse communities can be supported through inter-professional practice development. This article explores one such experience, that of speech and language therapists developing a new video-based coaching approach for teachers and teaching assistants in multi-cultural settings with high numbers of children learning English as an additional language. To support them in developing and trialling the coaching approach, the expertise of a teacher-educator and educational researcher was provided through a university business voucher. It is this working relationship that the article has as its practical focus, as it transformed to one of collaborative action research. The action research is described, providing the context for a discussion of the characteristics of collaborative action research and the proposal of a new model. This model offers a way of conceptualising collaborative action research through time, and of recognising the importance of the partners' zones of proximal, contributory and collaborative activities in sustaining change and knowledge-creation.