How does repetition affect vocabulary learning through listening to the teacher’s explicit instruction? The moderating role of listening proficiency and preexisting vocabulary knowledge

The study examines the effects of repetition on vocabulary learning within the context of three types of explicit aural vocabulary instruction – second language (L2) vs. codeswitching (CS) vs. contrastive focus-on-form (CFoF) – among 98 Chinese secondary school learners of English as a foreign language. It also explores how the effects of repetition on vocabulary learning were moderated by learners’ listening proficiency and preexisting levels of vocabulary knowledge. Within a 12-week pre–post test quasi-experimental design, learners listened to explicit vocabulary instruction for 20 target words, five of which were repeated four times, five repeated five times, five repeated seven times, and the remaining five repeated nine times. Findings suggested that regardless of the type of explicit instruction, vocabulary learning gains were positively correlated with repetitions but that at least seven repetitions were needed for significant gains to take place. In addition, the effects of repetition were moderated only by learners’ listening proficiency but not by their preexisting levels of vocabulary knowledge. Less proficient listeners benefited significantly more than more proficient listeners with every unit increase of the number of repetitions. The study illuminates important relationships between repetition and listening proficiency, factors useful to consider when designing pedagogical activities to enhance vocabulary learning through listening to explicit instruction.