Effectiveness of textually-enhanced captions on Chinese High-school EFL learners' incidental vocabulary learning

This study employed a mixed-methods approach to investigate the impact of textually-enhanced captions on EFL learners' incidental vocabulary gains and learners' perceptions of the captioning usefulness in a multi-modal learning environment. A total of 133 Chinese EFL high school learners of the low-intermediate level were randomly assigned to English captions with highlighted target words and L1 gloss (ECL1), Chinese and English captions (CEC), Chinese and English captions with highlighted target words (CECGW), and no captions (NC). Our quasi-experimental findings did not detect any significant differences among the caption types on vocabulary form recognition while ECL1 was found the most effective in meaning recall and recognition. Captioning types and learners' language proficiency exerted medium-to-large effects on meaning recall and meaning recognition. Our qualitative data suggested the participants generally viewed captioned videos positively, with variability in perceptions of concurrent presentation of information. The saliency of L1 gloss could direct the viewers' attention to the semantic features of a word and reinforce sound-form-meaning connections. Videos lacking L1 glosses of target words had relatively little effect on learners' vocabulary learning while more textual inputs might not necessarily result in vocabulary gains. Pedagogical implications are proposed for teachers' adoption of L1 in captioned videos to enhance learners' learning effectiveness.