The choice of language in the early years of schooling shapes children's opportunities to understand lessons, participate in classroom activities and develop literacy. The present paper will discuss the evidence in Nigeria on mother-tongue instruction and early literacy in the community of Yoruba speakers in Oyo State. It is qualitative in nature, library based and utilizes language-in-education policies, theories of language development, Ife Six-Year Primary Project and selected Nigerian and African studies. The literature suggests a clear pedagogical reason for teaching with familiar languages, with some evidence from Nigeria, but not consistent. The difference between outcomes of learning in home language and outcomes in school with different modes of instruction has received recent attention. The unevenness in the implementation of the provisions of earlier policy can be attributed to teacher preparation, appropriate reading materials, and parental expectations and linguistic diversity. The Federal Government's decision to end the former early primary mother-tongue-medium requirement is also taken into account for the review. It concludes that language choice needs to be taken into account in conjunction with the quality of instruction and children's language proficiency, and suggests that teachers can be supported, that materials used in the classroom should be locally appropriate, and that parent engagement and additional research in the classroom should be encouraged.