Effects of subtitles on vocabulary learning through videos: an exploration across different learner types

This study examines the effect of four subtiting conditions — no subtitle, intralingual subtitles, interlingual subtitles, and keyword subtitles — on vocabulary learning among diverse learner groups, as well as their perception of the effectiveness of subtitles. The study involved four participant types, all learning English as a foreign language: second-year primary school students (N = 147), fourth-year primary school students (N = 97), middle school students (year 8, N = 38), and high school students (year 10, N = 50). Participants watched videos under different subtiting conditions, followed by a vocabulary test. Our findings revealed that middle and high school students scored higher on vocabulary meaning recall when subtitles were provided. Meanwhile, second- and fourth-year primary school students did not benefit from the subtitles in terms of meaning recognition. Among the subtitle types, bilingual keyword subtitles were the most effective for middle school students, while interlingual subtities proved to be the best for high school students. Generally, the students' perception of the effectiveness of the subtitles in the experiment aligned with their actual learning outcomes.