Morphological instruction and reading development in young L2 readers: A scoping review of causal relationships

This scoping review explores the causal relationship between morphological in-struction and reading development in young L2 learners by synthesizing 12 primary studies published between 2004 and 2019 (N = 1,535). These studies focused on reading English as the target language and involved participants between kinder-garten and Grade 12 from four countries (China, Egypt, Singapore, and the USA). Findings suggested that (a) morphological instruction led to consistent and positive gains in L2 children's morphological awareness and vocabulary knowledge, and the effect sizes (Cohen's ds) ranged from small to large; and (b) the relationship be-tween morphological instruction and other outcomes such as phonological aware-ness, word reading accuracy, word reading fluency, spelling, and reading compre-hension was inconclusive. Notably, transfer effects of L2 English morphological in-struction on novel word learning in English or on reading development in an addi-tional language were only examined and observed in four primary studies. Discus-sion was provided regarding future instructional and research design.