We present results from three acceptability judgement experiments investigating the effect of discourse linking (d-linking) and animacy on whether-islands and interactions with resumption in Greek and English. Based on Anagnostopoulou's referentiality hierarchy, we test the acceptability of four types of wh-phrases, what, what X, which X, which of X in a range of configurations (simple questions and questions involving extractions out of (non-island) that-clauses and whether-islands). We further test interactions between animacy and d-linking in English. Our results show that d-linking improves whether-islands in both Greek and English. However, d-linking does not alter the overall interactions: whether-islands remain mostly less acceptable than that-clauses. While acceptability increases overall as predicted by the referentiality hypothesis, we obtain two unexpected contrasts: (i) a contrast between which X and what phrases and (ii) an independent effect of animacy; who is better than what, on a par with which X phrases. These contrasts affect the acceptability of whether-islands but not that-clauses.We propose that what sets what phrases apart, is the contrast between kind-denoting (what) and ordinary individuals (which,who), which can be triggered by d-linking or animacy. This denotational hypothesis predicts that the distinction is only relevant for scopal islands like whether-islands. The denotational contrast affects the processing complexity of whether-islands. Kind-denoting wh-fillers have higher integration costs (in the sense of Gibson's complexity model). The denotation of the filler interacts with its complexity (e.g. who vs. which X); together, they may improve the acceptability of whether-islands; however, they cannot cancel their overall complexity, as they cannot cancel * We would like to thank John Hawkins, Philip Hofmeister, Napoleon Katsos and the editors of this volume for comments and suggestions.The first author acknowledges support by Education First.John Sprouse and Norbert Hornstein, eds., Experimental Syntax and Island Effects, 310-340. Cambridge: Cambridge University Press, 2013. the main scope island (i.e. the question intercepting the filler-gap dependency); thus, manipulations of the filler cannot restore the acceptability of whether-islands. Finally, a crucial overall conclusion is that alleviation of integration costs of the filler (through d-liking/animacy) has a stronger effect on improving whether-islands compared to cancellation of locality costs (through resumption).