Incidental vocabulary learning for primary school students: the effects of L2 caption type and word exposure frequency

Within instructed second language research, there is growing interest in research focusing on primary school vocabulary learning. Research has emphasized classroom-based learning of vocabulary knowledge, with growing focus on the potential for using captioned videos and increased word encounters. The present study investigated the effects of various captioning conditions (i.e. full captioning, keyword captioning, and no captions), the number of word encounters (one and three), and the combinations of these two variables on incidental learning of new words while viewing a video. Six possible conditions were explored. A total of 257 primary school students learning English as a second language (ESL) were divided into six groups and randomly assigned to a condition in which 15 target lexical items were included. A post-test, measuring the recognition of word form/meaning and recall of word meaning, was administered immediately after participants viewed the video. The post-test was not disclosed to the learners in advance. The group viewing the full captioning video scored significantly higher than the keyword captioning group and the no-captioning group. Repeated encounters with the targeted lexical items led to more successful learning. The combination of full captioning and three encounters was most effective for incidental learning of lexical items. This quasi-experimental study contributes to the literature by providing evidence which suggests that captioned videos coordinate two domains (i.e. auditory and visual components) and help ESL learners to obtain greater depth of word form processing, identify meaning by unpacking language chunks, and reinforce the form-meaning link.