Can Multilingual Environments Promote Scalable EdTech? Evidence from a Randomized Controlled Trial

At least half of the world’s population uses more than one language daily, and many learners engage with educational content in a language that differs from their primary language. Educational technologies are uniquely positioned to address this linguistic diversity by delivering equivalent instruction in multiple languages, thereby reaching large multilingual populations. However, for this potential to translate into meaningful learning at scale, EdTech systems must support multilingual instruction effectively. To date, there is limited empirical causal evidence examining how the language of instruction influences learning processes and outcomes in digital environments. In this study, we conducted a small-scale randomized controlled trial to examine the causal impact of the language of instruction on learning in a radio- and mobile-based engineering course, providing insights relevant to scaling learning in multilingual contexts. We compared learning with instruction in Leb Lango, a predominant local language used by the participants of this study, and English, the official language in the country. Our findings show that learners receiving instruction in Leb Lango achieved significantly higher aggregated performance than those learning in English. Instruction in Leb Lango enabled learners to engage more efficiently with the course material and progress through a greater amount of practice content. These results highlight that language plays a role in shaping how students engage with EdTech and suggest that, to maximize learning outcomes at scale, educational technologies should provide instruction and practice opportunities not only in English but also in local languages.