This article explores and discusses one of the main findings of the author's recent dissertation, namely that parents' and pupils' choice of language of instruction in formal schooling depends on its social prestige. The author first reviews the latest research on language in education in sub-Saharan Africa, and asks why indigenous languages are so rarely used in formal schooling in this region, despite political demands for their greater use and ample scientific research showing their positive effects. Burkina Faso exemplifies this seemingly contradictory situation. Indigenous languages and French are complementary in formal and non-formal schooling as well as in areas of informal education; however, a closer look at the areas of application of each language reveals that indigenous languages have lower prestige than French, as well as lower expected and required outcomes. This is one possible explanation for the low usage rates of indigenous languages in formal schooling and reveals the extent to which the choice of language of instruction depends on its social prestige.