The serial mediation effect of motivated behavior, self-efficacy, and self-regulation on L2 grammar attainment: A cross-cultural study of Polish and Iranian learners

This study investigates the serial mediation effect of motivated behavior on L2 grammar attainment, mediated by self-efficacy and self-regulation, among Polish and Iranian university students. A total of 766 participants, 380 Polish and 386 Iranian L2 learners, were recruited to explore these relationships. Data were collected by means of self-report instruments and a researcher-developed grammar test. Descriptive statistics, measurement invariance testing, and structural equation modeling (SEM) were used to analyze the data. The findings revealed a positive direct effect of motivated behavior on self-efficacy and self-regulation, which in turn exerted a positive influence on grammar attainment. Measurement invariance testing confirmed that the constructs were interpreted similarly across both cultural groups. These results support the proposed serial mediation model, suggesting that motivated behavior fosters grammar learning through the development of self-efficacy and self-regulation. The study contributes to a deeper understanding of the psychological mechanisms underlying L2 grammar learning and offers valuable insights for pedagogy.