Throughout the nineteenth century, driven by the need both to communicate with potential African converts and to produce written Scriptural translations, Christian missionaries set about studying, transliterating and transforming South African languages. Their work served, in various ways, the demands of the developing British colonial order; established new ‘standard forms’ of South African vernaculars; and facilitated the development of literacy among African people in the region. The close relationship between missionaries, colonialism and language study in South Africa has been documented and analysed by scholars from a wide range of disciplines. This article summarizes some of the key issues in the field, as they have defined critical debates since the 1980s, by focusing on models of ‘invention’ on the one hand and ‘reciprocity’ on the other, and exploring continuities and dissonances between these debates and the wider fields of colonial studies and colonial discourse analysis. It concludes by arguing for a balance. On the one hand, it is vital that we acknowledge the significance of missionary language study as a mode of colonial discourse with the power to shape the social, linguistic, and political realities it purported only to describe. On the other, this should not eclipse our understanding of missionary linguistic work in social context, as the product of fraught, complex, and often mutually transformative encounters between European missionaries and African speakers of the languages in question.