Contrastive Analysis of Igbo and Yoruba Tonal Systems: Implications for Second Language Acquisition in Nigeria

This study conducts a systematic contrastive analysis of the tonal systems of Igbo and Yoruba to derive second language acquisition implications for Yoruba learners of Igbo and Igbo learners of Yoruba within the Nigerian bilingual educational context. Despite the political and demographic significance of Igbo-Yoruba bilingualism in cities like Lagos, Ibadan, and Abuja, virtually no controlled comparative study of tonal interference between these two major languages has been published. The study employs a threefold methodology: a formal linguistic contrastive analysis of Igbo and Yoruba tone inventories and tone sandhi rules using published descriptive grammars; an experimental production study in which forty Yoruba-dominant bilinguals produce Igbo tonal minimal pairs; and a perception study examining forty Igbo-dominant bilinguals' recognition of Yoruba tonal contrasts. Error analysis and acoustic measurements inform the contrastive interference profile. Findings reveal that Yoruba learners of Igbo demonstrate systematic high-tone downstep errors attributable to Yoruba's simpler downstep application rules, while Igbo learners of Yoruba show mid-tone instability linked to the absence of a comparable category in Igbo. The study generates specific tonal interference predictions and proposes a contrastive tonal pedagogy for Nigerian bilingual education contexts. Keywords: Igbo tone, Yoruba tone, contrastive analysis, second language acquisition, tonal interference.