The chapter begins with the discussion of the story about the tower of Babel and the confusion of tongues (Gen 11.1–9), the event which was usually but not always understood as the start of linguistic diversification. The chapter explores early Christian ideas about the primordial language, usually identified with Hebrew. The history of Hebrew and the attempts of late antique Christians to define their relations to this would-be original tongue occupy the larger part of the chapter. Fourth- and fifth-century writers discussed whether the original tongue ceased or continued to exist after Babel, and who – Heber or Abraham – was instrumental in preserving the original tongue. These biblical figures and various scenarios of language history they represented were claimed by competing Christian and Jewish historical discourses. These linguistic discussions contributed to consolidating their corresponding religious identities. The alternatives to the idea of Hebrew’s primordiality were also attested; they bear witness to the continuous debates about originality, ontological power, and the relative prestige of languages in Late Antiquity. The chapter attempts to reconstruct Christian attitudes to the linguistic diversity, their views on the history and evolution of other (non-Hebrew) languages, and to contextualize ideas about the language of God in Jewish–Christian polemics.