The impact of explicit instruction on different types of linguistic properties

Over the past decades, L2 research has shown that properties involving the syntax-discourse interface are typically more complex to acquire than strictly syntactic properties. To determine whether the complexity of the target property moderates the effectiveness of explicit instruction, this study investigates the impact of explicit instruction on the development of a syntactic property (the ungrammaticality of free inversion) and a syntax-discourse property (the unacceptability of locative inversion with informationally heavy verbs) in L1 European Portuguese-L2 English (B2 and C1 levels), using a pre-test/post-test design. Results reveal that instruction only produced lasting effects when it targeted syntax and learners were at the C1 level. These results indicate that syntax may be more permeable to instructional effects than the syntax-discourse interface and that the effectiveness of explicit instruction depends on learners’ stage of L2 development.