Contrastive Analysis of Negation in Yoruba and English and Its Implications for ESL Teaching in Oyo State

Contrastive analysis of structural differences between learners' first language and the target language provides a principled basis for predicting and explaining grammatical errors in second language acquisition. This study presents a contrastive analysis of negation structures in Yoruba and English, examining syntactic position, scope, and double negation patterns, and considers the pedagogical implications of identified contrasts for ESL teaching in Oyo State secondary schools. The analysis draws on descriptive grammars of both languages and recent typological research, constructing a systematic comparison of negation marking across main clause, interrogative, and imperative constructions. Key contrasts identified include the pre-verbal placement of the primary negation marker in Yoruba compared to post-auxiliary English not placement, the acceptability of double negation in Yoruba compared to its non-standard status in English, and the absence of do-support in Yoruba negated questions. An error analysis of two hundred composition scripts and fifty oral production samples from Senior Secondary School students in Ibadan confirmed that these contrasts correspond to high-frequency error types in the learner corpus, validating the predictive utility of the contrastive framework. The study translates the contrastive findings into five targeted instructional activities designed for use in Senior Secondary English lessons and recommends their piloting in Oyo State as part of a broader evidence-based grammar instruction initiative. Keywords: contrastive analysis, negation, Yoruba, ESL teaching, Oyo State.