Nabataean Aramaic contains a large number of loanwords from Arabic. Together with other evidence, this has been taken as an indication that the Nabataeans used Aramaic as a written language only, while a Pre‐Islamic variety of Arabic was their spoken language. Based on a comprehensive review of the evidence, however, this article concludes that both Arabic and Aramaic were in spoken use in the Nabataean Kingdom and Late Antique Northwest Arabia. Departing from this modified understanding of the linguistic status of Nabataean Aramaic, various features of Pre‐Islamic Arabic are then examined based on the Nabataean evidence: the realisation of the voiceless sibilant /s/, nominal morphology, the reflexes of stem‐final *y, verbal syntax, and the lexicon.