Among contemporary scholars dedicated to examining the intersection of language and Islamic legal theory, Bernard G. Weiss’ contributions to the study of Islamic law frequently emphasise the paramount importance of linguistic inquiries and language analysis (al-mabādiʾ al-lughawiyya or mabāḥith al-alfāẓ) within the uṣūl alfiqh literature. By taking into account a few late-19th/early-20th century digests and manuals used in the madrasa curriculum, his doctoral dissertation Language and Orthodox Muslim Thought: A Study of “Waḍʿ al-Lughah” and its Development and his subsequent articles on ʿilm al-waḍʿ (1966, 1976, and 1987) provided an initial general overview of a new science called ʿilm al-waḍʿ to a Western audience, underscoring its significance within the framework of legal methodology. Nevertheless, the extensive 14th - 20th century exegetical literature of ʿilm al-waḍʿ, originating from the foundational al-Risāla al-Waḍʿiyya of ʿAḍud al-Dīn al-Ījī (d. 756/1355), as well as the contexts in which this short text emerged, remain largely unexplored and understudied. The linguistic investigations of basic elements of language (nouns, verbs, and prepositions) undertaken by early commentators and glossators on al-Ījī’s Risāla are mainly devoted to analysing the roots of signification but also to developing a semantic theory that filled critical gaps in various disciplines, like balāgha, uṣūl al-fiqh, and logic. In general, ʿilm al-waḍʿ (lit. the science of linguistic positing), which can be loosely rendered as “semantics of the parts of speech,” examines how terms come to convey their concepts and, particularly, how terms convey particular and individual, or universal and general concepts. The original scope of ʿilm al-waḍʿ aimed to elucidate how terms, such as prepositions and pronouns, are posited in a universal way yet ultimately convey particular and individual concepts. The innovative solutions provided by ʿilm al-waḍʿ for explaining the semantic properties of this group of terms were so influential that premodern scholars, mainly commentators and glossators on al-Ījī’s Risāla, expanded the scope of this science, developing a comprehensive semantic theory that encompassed all parts of speech and simple sentence structures, while also engaging with the ḥaqīqa-majāz dichotomy. This presentation will first offer a heretofore unprecedented survey of the emergence and subsequent formation of ʿilm al-waḍʿ as an independent, and yet interdisciplinary, science between uṣūl al-fiqh and ʿilm al-maʿānī wa-l-bayān. It will then present some aspects of the linguistic investigations undertaken by legal theorists prior to the emergence and establishment of ʿilm al-waḍʿ, in order to highlight the innovative and original contributions that this new discipline introduced into the broader discourse of the linguistic inquiries. Finally, it will offer some preliminary reflections on how ʿilm al-waḍʿ has impacted legal theorists’ analysis of language and uṣūl al-fiqh literature.