The use of a language in written and formal contexts that is distinct from the languages used in everyday communication – such as Latin in early modern Europe and Standard Arabic in the Arabic-speaking world, both past and present – comes with benefits, but also with costs. Drawing on publishing data from early modern Europe, this column shows that the Protestant Reformation led to a sudden and sharp rise in vernacular printing, such that by the end of the 16th century, the majority of works were printed in spoken tongues rather than in Latin. This transformation allowed broader segments of society to access knowledge. It also diversified the composition of authors and book content and had long-term consequences for economic development.