Legal modality and semantic shift of s hall in the Tanzanian bilingual constitution

Abstract This study examines the semantic and functional variability of the modal verb shall in the Tanzanian Bilingual Constitution of 1977, as revised in 2005, with particular focus on its English usage and Kiswahili realisations. Although traditionally associated with legal obligation, shall has been widely criticised in legal linguistics for its semantic ambiguity and functional instability. Using a semantic-pragmatic and comparative translation approach informed by Systemic Functional Linguistics and legal pragmatics, the study analyses 705 occurrences of shall , from which 60 clauses were functionally classified, and 28 bilingual parallel clauses were selected for detailed analysis. The findings reveal that shall performs multiple constitutional functions, including constitutive or existential commands, deontic obligations, prohibitions, procedural futurity, and declarative constitutional identity. While obligation remains dominant, significant functional expansion toward futurity and declarative meaning is observed. The study further shows that Kiswahili lacks a direct equivalent of shall , leading to systematic translation strategies involving morphological futurity (ta-), existential constructions (kutakuwa na), lexical obligation markers (wajibu, lazima), and prohibition markers (ni marufuku). These strategies indicate that legal translation operates as a process of functional reconstruction rather than linguistic equivalence. The study concludes that constitutional meaning in Tanzania is dynamically constructed through the interaction of grammatical structure, institutional authority, and bilingual translation practices. It contributes to legal linguistics, translation studies, and African multilingual constitutional scholarship by demonstrating that legal modality in postcolonial bilingual systems is contextually distributed rather than semantically fixed.