Re‐engaging the interface debate: strong, weak, none, or all?

In the history of SLA research, the relationship between explicit and implicit knowledge has incited heated debate, culminating in, broadly, three disparate positions: (a) the non‐interface; (b) the weak‐interface; and (c) the strong‐interface. In this paper, we re‐engage the theoretical debate. Unlike the previous discussions, however, which typically find researchers espousing one position against another – usually the non‐interface position, we claim that in the interlanguage of any L2 learners, there is likely both explicit and implicit knowledge, but, more important, three types of relationships co‐existing between them: a strong interface, a weak interface, and no interface. We argue that further advances in SLA research would benefit from a concerted effort to identify which aspects of grammar are susceptible to a strong, weak, or no interface relation.