Each grammatical construction has its own function, and typically multiple constructions are combined to express a message. When the functions of two constructions conflict in a way that cannot be reconciled, their combination is judged ungrammatical. Here we consider one such type of case: “syntactic island violations.” Specifically, we consider combinations of wh-questions with 11 other constructions. Wh-questions request direct information about a particular constituent. Using a new Discourse task, we quantify how directly 11 constructions convey information in simple declarative sentences. Results demonstrate acceptability judgments on the wh-questions correlate with the degree to which the 11 constructions convey information directly. Thus, we argue that degrees of unacceptability of “island violations” result from the extent to which the discourse functions of the constructions involved conflict (N=240).

The current work tests the hypothesis that the island status of clausal adjuncts, as determined by judgments on wh-questions, are predicted by the degree of “backgroundedness” of the adjuncts, as determined by a separate negation task. Results of two experiments support the hypothesis that acceptability of extraction from adjuncts in wh-questions is inversely correlated with the degree to which the adjunct is backgrounded in discourse. Taken together, results show that temporal clausal adjuncts (headed by before, after, while) are stronger islands than adjuncts that are causal (here, headed by to or by). This demonstrates that adjuncts differ in degree of island status, depending on their meaning, despite parallel syntactic structure.