<p>This study explores the evolutionary trajectory of pragmatic functions in legal texts through a cross-temporal analysis of illocutionary act distributions, juxtaposing pre-modern legal codes (e.g., Hammurabi’s Code) with contemporary legal instruments. Grounded in Austin’s speech act theory and extended grammaticalization frameworks, the research employs computational linguistics methods—specifically Support Vector Machine (SVM) classification—to systematically identify and quantify pragmatic functions, including commands, prohibitions, authorizations, and declarations. Diachronic trends are visualized via Tableau to map structural shifts in linguistic realization of legal authority over millennia. The findings reveal a robust pattern of grammaticalization: pre-modern texts predominantly utilize direct, deontically charged imperatives, whereas modern legal discourse exhibits a marked shift toward conditional, modalized structures that embed illocutionary force within syntactically complex, rule-based formulations. This transformation not only validates the hypothesis of pragmatic grammaticalization in legal language but also underscores the interplay between linguistic evolution, institutionalized legal rationality, and sociocultural shifts toward procedural justice. By integrating authentic translational examples and cross-jurisdictional comparisons, this study contributes to interdisciplinary scholarship at the intersection of legal linguistics, historical pragmatics, and computational discourse analysis.</p>