Asking the simple question of why writers in one language commented on works composed in another opens up a set of questions and problems for thinking through the relationships between languages and literary cultures and their development over time. The archive of Hindi literature—a set of literary vernaculars that came into use at the end of the fourteenth century and were assimilated into the modern standard language of Hindi during the nineteenth and early twentieth centuries—contains a wealth of commentarial literature, including commentaries in which Hindi writers commented on texts in Sanskrit—the privileged ‘cosmopolitan’ language of literature, science, and scripture. Despite the ubiquity of such commentaries, they have received almost no attention from modern scholars—the result of certain nationalist modes of literary historiography that counterpose Hindi and Sanskrit. This article attempts a preliminary history of commentarial writing in Hindi, outlining the motivations, strategies, and techniques behind different types of commentaries that were composed during the fifteenth to eighteenth centuries. Even this brief survey of commentarial writings reveals not only how writers thought about the relationship between Hindi and Sanskrit—which they understood to be two distinct species or modes of language—but also the techniques and operations through which they created new lexicons and metalanguages in the vernacular of Hindi. These commentaries reflect a type of renaissance that occurred during the sixteenth to eighteenth centuries in northern India, characterised by new types of interpretive and analytical engagements with ‘classical’ works.