In his 1875 description of the language, Theodor Nöldeke describes Mandaic as among the purest of the Aramaic languages and the furthest from Western Aramaic, particularly with respect to its lexicon. As Mandæans identify their faith with that of John the Baptist and his community of followers, this observation is not without relevance for assessing the veracity of their accounts and reconstructing their history prior to the advent of Islam. Departing from the assumption that these accounts are either inaccurate or willfully dishonest, all recent descriptions of the Mandaic language maintain that it is completely free from any western influences whatsoever, employing a considerably stronger form of Nöldeke’s original claim. This article subjects the strong form of this claim to a critical analysis, surveying the evidence for western influence upon the lexicon of the Mandæan scriptural canon, principally the Canonical Prayerbook, the Great Treasure, and the Mandæan Book of John. It finds that these works contain numerous lexemes of Hebrew, Greek, Latin, and Western Aramaic origin that are otherwise unparalleled within Eastern Aramaic, and concludes that the scholarly consensus must either be revised to account for this evidence or abandoned.