This book by Hugo David investigates the beginnings, in the 10th century CE, of an autonomous reflection on language in the non-dualist trend of Brahmanical exegesis (Advaita-Vedanta) inaugurated in the 8th century by Sankara. Its starting point is a detailed study of the most ancient text exclusively devoted to linguistic issues belonging to that tradition, which is translated here for the first time in a western language, and of its only known Sanskrit commentary. On this basis, an attempt is made to understand why Prakasatman, one of the most illustrious non-dualist thinkers, engaged in an entirely new reflection on language, unknown to his predecessors. This approach, centred on hermeneutics rather than doctrine, allows one to understand how philosophy of language came to occupy a prominent position in late Advaita, as the cornerstone of a system, where being, however immediate, presents itself through the medium of Sacred speech.