How effective is second language incidental vocabulary learning? A meta-analysis

Abstract There is a great deal of variation in gains found between studies second language (L2) incidental vocabulary learning, as well many factors that affect learning. This meta-analysis investigated the effects exposure to L2 meaning-focused input on learning with an aim clarify proportional occur through Twenty-four primary were retrieved providing 29 different effect sizes and total sample size 2,771 participants (1,517 experimental groups vs. 1,254 control groups). Results showed large overall for first follow-up posttests. Mean proportions target words learned ranged from 9–18% immediate posttests, 6–17% delayed Incidental similar across reading (17%, 15%), listening (15%, 13%), while (13%, 17%) conditions posttest. In contrast, proportion viewing posttests was smaller (7%, 5%). Findings also revealed amount varies according range moderator variables including learner characteristics (L2 proficiency, institutional levels), materials (text type audience), activities (spacing, mode input), methodological features (approaches controlling prior word knowledge).