THE CONVERSATION: What happened when a South African school switched from English to bilingual science tests

Well‑resourced mother‑tongue bilingual science lessons and tests can improve Grade 4 performance and parent involvement, suggesting scalable bilingual education across South Africa.

South African no-fee primary schools use African languages as well as English for teaching and testing. Before 2025, children started learning in their home language in the first three years and then switched to English in Grade 4 (aged 10 and 11). Now, bilingual education is extending gradually into the upper primary grades.

South Africa’s public basic education system serves roughly 12.7 million learners . 80% of these learn through a language that is not their home language.

I am an education researcher with a special interest in language across the curriculum in multilingual contexts. In a recent case study of a bilingual science learning intervention in a Cape Town school, I wanted to know how effective it was to teach and test in more than one language, and what parents thought of the approach. Past studies hadn’t made it clear whether parents usually supported it.

The study found that teaching and testing science topics in the children’s home language and English produced much better results than using English only, and that parents were in favour of it.

The results suggest that bilingual classroom teaching and assessment could be used more widely, and it’s important to make sure parents understand why.

The study took place in a school in Khayelitsha , in the Western Cape. The no-fee school attracts learners from a wide area because it is well run. At the time of the study, the school language policy was English medium in all subjects in Grade 4, including science. The principal, however, agreed to try the bilingual approach in science for the study.

We gave 168 Grade 4 learners a bilingual science textbook in English and isiXhosa, their home language. The same teacher taught four classes bilingually, and learners used both languages in writing in their exercise books. One class was given a bilingual test while the others wrote the conventional English-only test.

The findings showed that children were more engaged in their learning in class compared with similar aged children who were learning in English only. In our study children contributed more to class discussion and wrote more in their exercise books.

In addition, those who wrote the bilingual test, with all questions written in isiXhosa and English, scored an 86% pass rate. Those who wrote the English-only test scored a 51% pass rate.

The parents of the children in the study said during a feedback session after the test was written that they were very happy with the programme. They commented on how the bilingual textbook connected them with their child’s learning at home.