Vocabulary knowledge has been proved to be fundamental for the improvement of all four aspects of second language learning (listening, reading, writing, and speaking). Therefore, research into vocabulary learning and teaching has received significant attention in the past two decades.

Teenagers in a large classroom. The view is of three students in the back row, paying attention to the teacher at the front.

Traditionally, vocabulary knowledge can be acquired either incidentally or intentionally. The former encourages a more natural way of learning, for example, learners unconsciously picking up unknown words during reading or listening in a second language. The latter, on the other hand, refers to any kind of pedagogical activities with an intention to contributing to learning new words. This could take the form of memorising unknown words from dictionaries or teaching new words in the classroom.

Learning through listening

Research has shown that compared to learning through reading, the amount of new vocabulary that can be acquired through listening is usually limited. In the classroom context, explicit instruction about the meaning of words orally from the teacher would allow learners to pay attention to the new vocabulary, hence increasing noticing and further enhancing learning through listening.

It is, however, unclear whether increasing the number of times learners receive explicit instruction about a word would lead to better learning and how far learners of different second language proficiency levels (for example, existing levels of vocabulary knowledge; listening proficiency) benefit from such repetitions. These are all the questions my study investigated.

This study involved 98 high school Chinese learners of English from three classes. Each class received a different type of explicit vocabulary instruction through a 12-week classroom intervention. Before the intervention, participants were assessed on their pre-existing vocabulary knowledge, listening proficiency, and their knowledge of the 20 words to be taught.

Learning through repetition

All 20 words were taught in the first three intervention sessions and revisited in the following six review sessions. Among the 20 words, five words were repeated four times, five repeated five times, five repeated seven times, and the remaining five repeated nine times. One week after the final review session, learners were tested on their knowledge of the 20 words once again.

The data were analysed to determine how vocabulary learning was affected by listening to the three different types of explicit vocabulary instruction for words repeated four, five, seven, and nine times respectively and how learners’ pre-existing vocabulary knowledge and listening proficiency affected how well they benefited from repetitions.

Findings suggest that regardless of the different types of explicit vocabulary instruction, vocabulary learning was improved by increasing the number of repetitions. However, at least seven repetitions were needed for successful vocabulary learning to take place through listening to explicit instruction. In addition, learners’ listening proficiency was an important factor influencing how well they benefited from repetitions.

Less proficient listeners benefited to a greater extent than their more proficient peers when the number of repetitions increased. Regardless of the number of repetitions, there was a consistent advantage in favour of learners with a lower level of pre-existing vocabulary even when the number of repetitions was as low as four.

Overall, the study findings suggest that it is important for language teachers to consider incorporating repetitions when teaching vocabulary through listening to explicit instruction. Additionally, when planning vocabulary learning activities, teachers need to include at least seven repetitions of the new words to promote maximal learning effects. Moreover, learners’ existing listening proficiency needs to be taken into account when teaching new vocabulary and designing learning tasks, in particular for tasks that require learners to learn from listening.

For learners who are less proficient in listening, providing them with more opportunities to listen to the new words, hence increasing the number of repetitions may further help them to learn more.

Pengchong Anthony Zhang is Lecturer in Education (Second Language Learning) at the University of Reading and winner of the University’s 2023 Research Output Prize (Prosperity & Resilience theme) for his study published in Language Teaching Research, ‘How does repetition affect vocabulary learning through listening to the teacher’s explicit instruction?’.