Variation in English Vocabulary Depth among Tanzanian Secondary School Learners: The Role of Sociolinguistic Background

This study examines how sociolinguistic background affects the development of English vocabulary depth among secondary school learners in Tanzania’s multilingual context, where English serves as the medium of instruction from secondary to tertiary education, despite being primarily learned as a foreign language. Despite growing interest in vocabulary acquisition, there is limited empirical evidence on how sociolinguistic factors shape vocabulary depth among secondary school learners in Tanzania. A convergent parallel mixed-methods design was adopted to triangulate quantitative and qualitative data. Using stratified random sampling, the Word Association Test was administered to 320 Form 3 and 4 students from eight secondary schools in Dodoma, and interviews were conducted with eight English teachers to provide deeper insight. Multiple regression and thematic analyses revealed that sociolinguistic background significantly affects learners’ vocabulary depth (p < 0.05). Students who reported using English in informal settings, such as the playground or at home, demonstrated greater vocabulary depth than those who used English only in formal classroom contexts. In addition, learners whose parents had attained at least Form Four education and those who began learning English in early schooling exhibited more developed lexical networks than their peers. These findings highlight the importance of sociolinguistic exposure and early language-learning experiences. The study suggests that language-teaching and language-learning policies should consider learners' sociolinguistic diversity and provide a basis for targeted pedagogical interventions.