This paper explores the relationship between linguistic diversity and the stock of health information in society. Information is measured using individual-level knowledge about the oral rehydration product for treating children with diarrhea. Exploiting an individual woman-level dataset from the Demographic and Health Surveys for 14 sub-Saharan African countries combined with a novel high-resolution dataset on the spatial distribution of linguistic groups at a 1 km × 1 km level, this study shows that linguistic diversity has an inverted U-shaped relationship with the stock of information in society.