This article explores how ordinal numerals (like first, second and third) can help classify languages, focusing on the Semitic language family. Ordinals are often formed according to productive derivational processes, but as a separate word class, they may retain archaic morphology that is otherwise lost from the language. Together with the high propensity of ‘first’ and, less frequently, ‘second’ to be formed through suppletion, this makes them highly valuable for diachronic linguistic analysis. The article identifies four main patterns of ordinal formation across different Semitic languages. Together with innovations in the lowest two ordinals, these can be correlated with more and less accepted subgroupings within Semitic as a whole. Concretely, they offer support for the widely accepted West Semitic, Northwest Semitic and Abyssinian (Ethio-Semitic) clades as well as the recently proposed Aramaeo-Canaanite clade and provide new evidence for the further subclassification of Abyssinian that matches other recent proposals. However, no evidence was found to support the debated Central Semitic or South Semitic groupings. Given the accurate identification of accepted subgroupings and high level of detail, this approach holds promise for the classification of other language families, especially where other linguistic data are scarce.Descriptive and Comparative Linguistic
