When Modern Hebrew was revived as Israel's national language, a pronunciation debate emerged between two ancient traditions: Sephardic and Ashkenazic Hebrew. Through extensive analysis of Masoretic texts, ancient Greek, Latin, and Arabic transliterations, and comparative Semitic linguistics, this research traces how these distinct pronunciation systems evolved from a common source. Evidence from sources spanning the Septuagint (2nd century BCE) to medieval Jewish texts reveals that Sephardic pronunciation preserves an older tradition maintained in Babylonian Jewish communities. A crucial phonological shift occurred in Palestinian Hebrew between the 2nd-5th centuries CE, transforming long "ah" sounds into "o" sounds—a change that paralleled similar developments in Syriac and Coptic languages, suggesting a broader regional phenomenon. The Tiberian Masoretes, working after this sound shift, codified their vowel system according to the newer Ashkenazic pronunciation, while Babylonian communities retained the pre-shift Sephardic tradition. Although Sephardic pronunciation represents an older historical form, both systems claim legitimate antiquity, with Ashkenazic pronunciation dating to at least the 6th century CE and embodying the influential Tiberian Masoretic scholarly tradition.