The Effect of Explicit Grammar Instruction on the Acquisition of English Aspect Marking by Fulfulde L1 Learners

The role of explicit grammar instruction in second language acquisition has been intensively debated for decades, with recent research increasingly supporting the position that explicit instruction of specific grammatical structures produces measurable and durable learning advantages under defined conditions. This study empirically examines the effect of explicit instruction on the acquisition of English aspectual marking, specifically the progressive and perfect aspects, by Fulfulde L1 learners in Adamawa State secondary schools. A quasi-experimental design with pre-test, instruction, immediate post-test, and delayed post-test compared three groups: an explicit instruction group receiving form-focused explicit grammar instruction with metalinguistic explanation, an implicit instruction group receiving only structured input exposure, and a control group receiving standard textbook instruction. Each group comprised forty Senior Secondary School students in Yola North. Instruction was administered over six lessons across two weeks, with tests targeting both accuracy of aspect marking in written production and grammaticality judgment. Analysis of variance results show a significant group by time interaction, with the explicit instruction group outperforming both comparison groups on immediate post-test measures for both progressive and perfect aspect accuracy, with gains maintained at the six-week delayed post-test. The implicit group shows significant progressive aspect gains but not perfect aspect gains, consistent with the greater formal complexity of the perfect. The study contributes empirical support for the role of explicit instruction in aspect acquisition by L1 Fulfulde learners. Keywords: explicit grammar instruction, aspect marking, Fulfulde L1, second language acquisition, Adamawa State.