Indigenous communities, linguists, teachers, and language activists have been developing methods to revitalise endangered languages over several decades. Not only are these methods diverse, they are usually implemented in various ways according to local needs and aspirations. Language revitalisation methods focus on proficiency, but there is also interest in strengthening identity, resilience, and wellbeing. Aside from a handful of successes, programs may not be achieving desired outcomes. One could try to evaluate specific programs. However, we believe that a necessary first step is to examine published literature of revitalisation efforts to develop initial understandings of how they work. In particular, we seek to understand how revitalisation efforts tap into the speech community, how local participation affects outcomes, and how this involvement is supported and sustained by external programs, with a focus on language revitalisation efforts in Australia. We conduct a realist synthesis, and through analysis of 125 pieces of literature, we identify 13 initial theories. In analysing these theories, we identify two major gaps in our understanding of language revitalisation: how revitalisation programs work to strengthen communities and promote commitment. We propose these as significant, under-theorised elements of successful revitalisation which can guide exploration at the level of individual programs.