Epistemic Modality in Yoruba: Syntactic and Semantic Properties

Epistemic modality, the linguistic encoding of a speaker's assessment of the certainty, probability, or evidence status of a proposition, is a cross-linguistically significant category that remains understudied in Yoruba formal linguistics. This study investigates the syntactic and semantic properties of epistemic modality expressions in Yoruba, drawing on elicited sentence data and naturalistic discourse recorded from 45 native speakers in Osun and Oyo States, South West Nigeria. The study documents and classifies epistemic modal expressions including lexical modal verbs, adverbial modifiers, and sentence-final modal particles, examining their distribution, scope, and the evidential distinctions they encode. The theoretical framework integrates possible worlds semantics with typological modal theory and cross-linguistic evidentiality research. Existing formal semantic work on Yoruba has focused primarily on aspect, tense, and negation, with epistemic modality as a distinct grammatical category being comparatively underdeveloped in the literature. This study fills that formal semantic gap. The research investigates whether Yoruba distinguishes inferential from reportative epistemic sources, how epistemic modals interact with negation and aspect, and whether any morphological categories systematically encode epistemic distinctions alongside other grammatical meanings. Findings are expected to reveal a productive but analytically complex epistemic modal system in which lexical and syntactic strategies combine with pragmatic inference to convey epistemic meaning. Recommendations will address the inclusion of formal semantic analysis of modality in Yoruba linguistics graduate curricula and future Yoruba-typological comparative studies. Keywords: epistemic modality, Yoruba, formal semantics, modal verbs, evidentiality.