Abstract Despite growing advocacy for mother tongue education in multilingual societies, limited empirical evidence exists on its comparative impact across different school types in Nigeria. This study examined the impact of using students’ first language as the medium of instruction on academic performance in elementary public and private schools. Utilizing a mixed-methods approach, the study included both quantitative and qualitative data collection from 200 students (100 from public schools and 100 from private schools) and 10 teachers across Ibadan South-West Senatorial District. Academic performance was measured through standardized tests and assessments, while interviews provided insights into teaching practices and language use in the classroom. The major findings indicated that students who were taught in their first language (Yoruba) demonstrated significantly higher academic performance compared to their counterparts in English-medium private schools. Additionally, the study revealed that code-switching practices in public schools contributed to varying degrees of comprehension and engagement among students. The study concluded by emphasizing the need for educational policies that prioritize the use of first languages in instruction to enhance learning outcomes. This research contributes to the ongoing discourse on language in education in Nigeria and emphasises the importance of aligning teaching practices with students’ linguistic backgrounds for optimal academic success.
Olusegun Oladele Jegede (Mon,) studied this question.