The Effects of Code-switched Instruction on L2 Learning: a Research Synthesis

Abstract

The belief that language instruction should be done exclusively in the target language and that ‘native-speakers’ are better language teachers is still around. In this context, there are language teachers who perceive code-switching as detrimental to language learning, while others believe L1 usage should not be excluded and can enhance L2 learning (Tian & Macaro, 2012). Seeking to understand what recent research has found on the effects of code-switched instruction on L2 learning, we conducted a research synthesis of experimental studies published from 2008 to 2018. Our research questions were 1) what are the effects of code-switched instruction on second language learning?; 2) does code-switched instruction lead to better learning results than target-language-only instruction?; and 3) what are the learning contexts of the research investigating code-switched instruction and who are their participants?. Eight out of the nine studies found that the code-switched instruction outperformed instruction done exclusively in the target language, with positive effects, such as reduced anxiety, being reported in all of them. Considering our results, we argue that code-switching is not necessarily a sign of diminished linguistic competence and that it is not detrimental to language learning.