Towards a Unified Formal Account of Focus, Topic, and Information Structure in Yoruba

Information structural categories including focus and topic encode the discourse-level status of referents and propositions and interact with syntax, prosody, and pragmatics in complex ways that vary significantly across languages. This dissertation develops a unified formal account of focus, topic, and information structure in Yoruba, addressing the theoretical challenges posed by a tonal language in which prosodic marking of information structure must be negotiated alongside lexical and grammatical tone. Drawing on a corpus of 10,000 naturally occurring Yoruba clauses collected from recorded conversations, oral narratives, and broadcast media in South West Nigeria, and supplemented by experimental elicitation tasks conducted with 60 native speakers, the study maps the syntactic, morphological, and prosodic strategies through which Yoruba encodes focus and topic distinctions. The theoretical framework integrates Government and Binding theory, the cartographic approach to clause structure, and the alternative semantics theory of focus. Existing formal analyses of Yoruba information structure have addressed focus markers and left-dislocation constructions in isolation, without developing a unified interface account. This dissertation makes an original theoretical contribution by proposing a unified cartographic representation of Yoruba information structure that accounts for focus particle placement, topicalisation, contrastive focus prosody, and the interaction of information structure with Yoruba aspect markers. Findings will provide the most comprehensive formal analysis of Yoruba clause-level information structure to date. Recommendations will address the implications for Yoruba language teaching and natural language processing. Keywords: information structure, focus, topic, Yoruba formal syntax, cartographic approach.