This article revisits the linguistic periodization of the book of Jonah, focusing on E.B. Pusey’s 1860 commentary and its modern relevance. Pusey challenged claims that Jonah’s unusual lexicon and grammar required a post-exilic date, arguing instead for earlier, non-diachronic explanations such as dialect, foreign influence, and contextual usage. His nuanced treatment anticipated later methodological developments, especially the rule-governed approach of Avi Hurvitz, which identifies diagnostically late linguistic features through late distribution, classical opposition, and extrabiblical confirmation. Applying these criteria, the article surveys more than fifty features in Jonah deemed late by various scholars. Eleven emerge as strong indicators of lateness, while many others show partial or ambiguous significance, often explainable by genre, style-switching, or Phoenician/Aramaic influence. Taken cumulatively, the evidence suggests Jonah’s Hebrew belongs to a late stratum, most plausibly the sixth–fifth century BCE, within the Persian Period, though affinities with Rabbinic Hebrew complicate precise placement. While modern scholarship generally rejects Pusey’s pre-exilic dating, his sensitivity to methodological caution and non-diachronic variety remains instructive. Jonah thus stands as a linguistically peculiar text, chiefly Classical Biblical Hebrew, but with links to Late Biblical Hebrew, Rabbinic Hebrew, and Aramaic, that offers a valuable test case for theories of linguistic periodization.