Morphological Instruction’s Impact on English Learners’ Reading: A Meta-Analysis

Morphological awareness—the ability to identify and manipulate morphemes—plays an important role in English learners’ language and literacy development, yet the efficacy of morphological awareness instruction remains inconsistently documented. This meta-analysis synthesized experimental and quasi-experimental intervention research across diverse English learner populations, including ESL and EFL learners of various ages, to examine the effects of morphological awareness instruction on morphological knowledge, vocabulary, and reading comprehension. Using robust variance estimation to account for dependent effect sizes, results revealed significant positive effects on morphological knowledge (g = 1.00), vocabulary (g = 0.77), and reading comprehension (g = 0.91). Exploratory moderator analyses indicated larger effect sizes in EFL than ESL contexts for some outcomes, no statistically significant differences by age group, and an inverse association between intervention duration and vocabulary effect sizes. Findings provide promising evidence that morphological awareness instruction can support English learners’ literacy development, while substantial between-study heterogeneity and the modest evidence base warrant caution in interpreting moderator findings and generalizing across instructional contexts. This study extends prior syntheses by focusing on English learners across ESL and EFL contexts and by examining multiple literacy outcomes relevant to language and reading development.