Does informal digital language learning really contribute to second language achievement? Evidence from a multilevel meta-analysis

Research examining the relationship between informal digital language learning (IDLL) and second language (L2) achievement has proliferated over the past decade, yet consensus on the extent to which IDLL influences L2 achievement remains elusive. This study addresses this critical gap through a multilevel meta-analysis synthesizing 68 effect sizes from 47 empirical studies encompassing 22,242 participants. The three-level meta-analysis yielded a significant, positive average effect size (z = .49; r ≈ .45; p < .001), indicating a moderate association between IDLL and improved L2 achievement. Moderator analyses revealed that learning type, tool type, target language, learner background, proficiency level, context, and measurement type did not significantly moderate the IDLL-L2 achievement relationship. These findings suggest that the positive association between IDLL and L2 achievement is evident across diverse learner populations and conditions, though conclusions about uniformity should be drawn with caution. This study contributes to the field of informal language learning by substantiating the beneficial role of IDLL in L2 development while identifying future research directions in this rapidly evolving field.