Influence of Household Language Environment on Yoruba Proficiency of Pupils in Ile-Ife

The home language environment is widely recognised as a foundational determinant of children's first-language proficiency, affecting vocabulary breadth, syntactic complexity, and communicative fluency. This study examines the influence of household language environment on the Yoruba proficiency of primary school pupils in Ile-Ife, Osun State, South West Nigeria. Using a descriptive correlational design, data were collected from 240 primary four and five pupils and their parents or guardians across eight primary schools in Ife Central and Ife East local government areas. Yoruba proficiency was assessed through oral narrative tasks and written comprehension exercises adapted from standardised Yoruba language assessments. Parental language behaviour was measured via household language use questionnaires administered to primary caregivers. The study draws on the home-school language continuity framework and Vygotsky's sociolinguistic developmental theory. Reviewed literature consistently demonstrates a positive relationship between home language use and school language performance, yet Ile-Ife specific data remain limited. This research fills that gap and contributes to the growing body of work on Yoruba as a medium of instruction. The study investigates whether pupils from households where Yoruba is the dominant language significantly outperform those from English-dominant or bilingual households on Yoruba proficiency measures. Findings are expected to confirm a significant home language influence, with implications for parental guidance and early childhood language programmes. Keywords: household language environment, Yoruba proficiency, primary school pupils, Ile-Ife, first-language development.