ADVANCING VOCABULARY ACQUISITION THROUGH MORPHOLOGICAL INSTRUCTION: EVIDENC E FROM DUTCH EFL LEARNERS

This study investigates the effects of explicit instruction in derivationa l morphology on English vocabulary acquisition among Dutch high school students. Forty two learners participated in a pre test/post test intervention comparing two approaches: Focus on Forms (FoFs), emphasizing systematic teaching of ffixes, and Focus on F orm (FoF), embedding affixes in communicative contexts. Mixed factor ANOVA analyses revealed no significant overall effects of instructional type or time, though task type significantly influenced outcomes. Students consistently performed worse on derivati on tasks than on decomposition or sentence completion, with prefixes posing greater challenges than suffixes. These findings highlight the cognitive complexity of productive morphological tasks and the need for more targeted, sustained instruction. The stu dy underscores that while explicit morphological teaching may not yield immediate gains across all tasks, it illuminates task and affix specific difficulties that must be addressed in vocabulary pedagogy.