Is the semantics/syntax interface vulnerable in l2 acquisition?

We examine the L2 acquisition by English native speakers of the interpretation of DPs as signaled by mood in Spanish relative clauses. The choice of mood here depends on the specificity of the DP head, not on grammaticality. Modal contexts license non-specific interpretations of DPs and L2 learners only receive instruction on an extremely reduced subset of these. A truth-value judgment task and a sentence combination felicity task were administered to L2 learners and controls. Results show that advanced learners, but not intermediate ones, perform at near native levels, which provides evidence that interface phenomena, deemed difficult to acquire given their inherent complexity and the lack of direct evidence in the input, can in fact be acquired even in cases such as these, in which transfer is not at stake.