Transient but Effective? Captioning and Adolescent EFL Learners’ Spoken Vocabulary Acquisition

This study aims to establish the effects of captioning on enhancing EFL learners’ spoken vocabulary. To this end, a three-month experiment, which involved ten level-appropriate videos from the cartoon series, Olivia, was conducted. A quasi-experiment design was adopted with a total of 118 EFL eighth graders at a junior high school participating in the study. Sixty students were assigned to watch the videos with captions, and the others were assigned to watch them without. To explore if the efficacy of captioning would be modulated by the students’ linguistic competence profiles—an issue that a lot of EFL instructors are currently facing in their teaching—the participants were further subdivided into three groups (high-level, intermediate-level, and low-level) based on their achievements in English. Two types of vocabulary posttest (i.e., form recognition and vocabulary acquisition tests) were administered to evaluate any vocabulary gains. The results of the study indicate that the availability of captions significantly improved the participants’ recognition of form and form-meaning knowledge of novel L2 (English) spoken vocabulary. In addition, in both vocabulary tests, the participants with a higher level of linguistic competence acquired substantially more word gains from captions than their counterparts of lower competence. These results empirically established the efficacy of captioning in enhancing EFL eighth graders’ incidental vocabulary spoken vocabulary gains and suggest that linguistic competence appears to be a crucial factor modulating the pedagogical potency of captioned videos. Based on the findings of this study, some pedagogical implications for employing captioned video materials to enhance EFL middle school students’ language gains are discussed.