Effects of textual enhancement on L2 development: a meta-analysis

Abstract This meta-analysis examines the effects of textual enhancement (TE) on second language (L2) development by synthesizing findings from 29 primary studies involving 1749 participants. These studies were selected based on carefully defined inclusion criteria and an evaluation of the homogeneity of the primary studies’ effect sizes. The results reveal an overall small to medium combined aggregate effect size ( g = 0.54) for between-subject comparisons, suggesting that TE has a modest impact on L2 learning. Moderator analyses indicate that TE has equal effects on the development of grammatical and lexical knowledge. Additionally, the findings show that employing multiple TE techniques does not significantly enhance its effectiveness compared to using a single technique, suggesting a ceiling effect in how much TE can contribute to the noticing of target features. The results indicated a smaller effect size for learners with lower proficiency compared to those with intermediate and advanced proficiency levels, although the difference was not statistically significant. Finally, the findings indicated that the effect of TE on L2 development is not moderated by the mode of delivery (i.e., paper-based vs. digital materials). Overall, these findings contribute to the ongoing debate on the role of noticing in L2 acquisition, suggesting that while TE facilitates language learning, its impact may be limited and should be interpreted with care.