Choice of instructional language is influenced by both previous and current perceptions of the value of a given language. For many South African learners, this has contributed to their education being presented either partially or entirely in a second or third language. This effectively limits their cultural capital and educational opportunities. The negative impact of non-equivalence between home language and instructional language is arguably more influential for linguistically dense school subjects, for example Science more so than Mathematics. The Trends in International Mathematics and Science Study (TIMSS) 2015 data allows exploration of the relationship between language non-equivalence and academic achievement as well as its differential association across subjects. The current paper also aims to investigate this relative to the impact of other contextual factors on Science and Mathematics achievement. Secondary analysis was performed on South African Grade 9 TIMSS 2015 country data using multiple regression procedures. Variables related to language were included in modelling at the learner, teacher and school levels. Results indicated that learner-level factors greatly outweighed those from the teacher and school levels. In line with expectations, resource availability as well as home language and instructional language equivalence significantly predicted Mathematics and Science achievement. Furthermore, the impact of language equivalence was higher in Science achievement. These results indicate that improvement of the processes leading to instructional language proficiency, be it at learner, teacher or school level, will contribute to higher academic achievement amongst South African learners and indeed for international second-language learners. With regard to classroom Science teaching and learning, it is also motivated that teachers need to be cognisant of the continuing impact of language for learners as they may need to incorporate innovative techniques and/or guidance.
Human Sciences Research Council (Sat,) studied this question.