Abstract
Second language (L2) learning is a complex process influenced by various factors, including emotions and metacognition (MC). While several studies examined these factors individually or focused on adult samples, little is known about the combined effect of MC and achievement emotions, and their long-term effects on L2 learning remain unknown, particularly among school-age learners. To address this gap, Italian primary school children were assessed longitudinally at four time points between 2021 and 2024. Children were evaluated on their English vocabulary, MC monitoring and control of their performance on the English vocabulary, and achievement emotions related to English as L2 (enjoyment, boredom, and anxiety). Results revealed a significant effect of time on English vocabulary and all other measured variables. MC monitoring and control, as well as anxiety, emerged as key predictors of English vocabulary. This study highlights the relevant role of MC and emotions in L2 learning over primary school.