Working memory of young school-age learners acquiring L2 English morphology: An experimental exploratory lab study with structured input intervention

The aim of this pre-/posttest design lab case study is to find possible interactions between working memory (WM) effects and the effectiveness of structured input among 10-11-year-olds with first language (L1) German children. The target feature is the simple English past tense. The WM capacity was assessed via three span tasks: listening (LST), reading (RST), and a digit span task (DST). Second language (L2) learners' WM scores for all three span tasks were included as continuous predictors in the mixed model analysis. Assessment entailed sentence-level interpretation tasks yielding accuracy scores with reaction times, and a gap-filling production task with accuracy scores. Regarding interpretation, results varied. L2 learners with high DST scores outperformed learners with low DST scores in terms of accuracy. A mixed model analysis including reaction times did not improve the model's fit. Regarding production, the WM did not prove to be a predictor for the accuracy effects. However, L2 learners with early age of onset English (AOE) showed significant improvement over time and L2 learners with late AOE showed no effect at all. We conclude that instruction with structured input is effective regardless of the WM score, and its effects are retained over a 3 weeks' delayed period. • The current experimental exploratory lab study investigates the effects of structured input on the acquisition of L2 English past simple tense by L1 German young school-age learners. • L2 learners of English with high working memory scores on the digit span task are better in interpretation than those with low scores. • The positive results generated by structured input practice on the production task were not affected by working memory.