When schools teach pupils in their mother tongues, it helps their reading in their own languages and may also improve their reading in other languages. Pooja Nakamura, Adria Molotsky, Rosa Castra Zarzur, Varsha Ranjit, Yasmina Haddad and Thomas de Hoop discuss the findings of a CEDIL-funded systematic review that examines the impact of language of instruction policies on literacy outcomes.

A shocking 70% of all 10-year-old students in low- and middle-income countries (LMICs) cannot read a simple text. An average of 40% of those students are educated in languages they do not use or understand, and most of them will then need to transition to education in a new Language of Instruction (LoI).

There is now substantial evidence that mother tongue-based multilingual education (i.e., the child is taught in their “own” language first) has multiple benefits (Evans & Acosta, 2020; Collier & Thomas, 2017; Nag, Vagh, Dulay, & Snowling, 2019). At the same time, there is a well-established link between postcolonial languages and socioeconomic mobility, leading to high demand for earlier and earlier introduction to these languages in schools (Azam, Chin, & Prakash, 2013; Coleman, 2011). Other factors that complicate LoI choices include linguistically heterogenous classrooms, lack of teaching and learning materials, limited trained teachers, and lack of political or community will (Piper, Zuilkowski, & Ong’ele, 2016; Trudell & Piper, 2013).

This leads to a situation in which decision-makers must reconcile both the well-documented benefits of mother-tongue instruction along with the quest for socioeconomic mobility through a postcolonial or international (later acquired) language at earlier grades.

We conducted a systematic review, funded by the CEDIL programme and due to be published soon, focused on reconciling these evidence gaps by examining the impact of LoI choices – especially mother tongue education as well as the timing of transition to a new LoI – on primary school literacy outcomes in LMICs. Specifically, we examined the effects mother tongue-based education policies and LoI transition policies on students’ literacy, biliteracy, and multilingual literacy skill development. The review summarized evidence from 45 high-quality studies conducted in low-and middle-income countries, primarily in Sub-Saharan Africa and South and Southeast Asia. The studies examined includes education in a range of native languages, lingua francas like Kiswahili and Amharic, as well as later acquired post-colonial languages, such as English, French, and Portuguese. The studies included 11 randomized controlled trials, 11 quasi-experimental studies, seven cross-sectional studies, and 16 qualitative studies.

The findings reiterated that mother tongue reading programs lead to significant impacts on mother-tongue reading scores. There was also some evidence that mother tongue reading programs have significant impacts on English (or later acquired language) reading scores. However, the results were not conclusive in terms of impact of mother tongue instruction on learning outcomes after the transition to a new LoI.

As such, there is a lack of high-quality evidence on the trade-off between putting resources in high-quality English LoI versus high-quality mother tongue education and then transitioning to English LoI. There is also a large gap in the evidence determining when students should transition to a new language of instruction and how such decisions should differ by context.

Recommendations for next steps

Based on our systematic review, we make the following policy recommendations for next steps:

1. Continue to invest in teaching students in their “own” languages first.
2. Investigate with high-quality studies (that meet rigorous quality standards against a variety of biases) whether – and if so, in what ways and why – mother tongue education programs impact literacy and other academic outcomes in not only the mother tongue, but also in the “later acquired” languages.
3. Conduct cost-effectiveness analyses to help provide decision makers with the trade-offs that are inherent in determining how much time and resources should be spent teaching in one language versus another.

Our review contributes to the mounting evidence that the initial LoI must be in a language children understand best. However, there is still a dire lack of evidence on how best to transition from one LoI to a new one – even though most students across low- and middle-income countries are being educated in multilingual environments in which transition will occur. Our team is currently examining several dimensions of LoI transitions across seven countries, and we plan to update this systematic review as new evidence comes to light on LOI transition.

This blog post relates to a systematic review that will be published soon in Campbell Systematic Reviews.

Cover photo: GPE/Kelley Lynch