This study examined how Saudi learners of English as a foreign language (EFL) developed collocational competence through strategic engagement, and how institutional context and Arabic first language (L1) interference mediated this process. A total of 120 male English majors from public and private universities participated in a two-semester longitudinal mixed-methods design. Instruments included CEFR-aligned vocabulary tests, collocation tasks, strategy inventories, reflective logs, and essay analysis. Quantitative findings revealed significant gains in vocabulary knowledge and strategy use, with B2 learners demonstrating a marked shift toward metacognitive regulation. Regression analyses showed that collocational depth, measured by accuracy and sophistication, was a stronger predictor of CEFR-rated writing quality than vocabulary size. Error analysis indicated persistent first language (L1)-based interference (literal translation, verb overgeneralization, idiomatic transfer), though these errors declined with proficiency and were less frequent among private-university learners, likely due to stronger digital exposure and feedback mechanisms. Qualitative data underscored motivation, teacher/peer feedback, and digital engagement as key drivers of cognitive and affective involvement in collocational learning. Together, the results highlighted the dynamic interplay between lexical depth, L1 transfer, and engagement, showing that collocational competence evolved through both individual strategies and institutional affordances. By integrating CEFR-based assessment, collocational analysis, and engagement theory, this study extended vocabulary research in Saudi contexts. Pedagogically, it called for collocation-focused strategy instruction, affective support to mitigate L1 interference, and equitable institutional resources aligned with Saudi Arabia’s Vision 2030 educational agenda.
Mohammed Hassan Alshaikhi (2026) studied this question.