This chapter considers two case studies exemplifying different models of small-scale, mediated intervention research in Modern Foreign Language (MFL) classrooms. By ‘mediated’, we mean that they are thoroughly grounded in both theoretical and practical perspectives, such that practical concerns are mediated by research understandings, and vice versa. Both studies focus on the development of assessment practices at a time when recent changes to the National Curriculum in England have resulted in the removal of the previous well-established assessment framework. The first was carried out by a teacher as part of an examined Master’s-level research project, the second by university academics working collaboratively with other practitioners within a multi-level Initial Teacher Education partnership. Both studies illustrate how a thoroughly research-informed approach can be useful in addressing practical classroom problems. We also argue that such mediated, small-scale studies can be a valuable first step in a wider process of systematically developing and evaluating pedagogical innovations – provided that sufficient opportunities for dissemination are found, which may currently be limited in the case of practitioner research. Finally, we highlight the value of these studies as vehicles for professional learning, as one way of developing teachers’ research literacy.