Tsimpli and Dimitrakopoulou (2007) propose the Interpretability Hypothesis (IH), according to which uninterpretable features present an insurmountable difficulty in adult second language acquisition. The experimental study supporting the IH examines Greek native speakers’ knowledge of gaps versus resumptive pronouns in English wh-movement. A crucial assumption is that Greek allows resumptives optionally. Alexopoulou and Keller’s (2002, 2007) findings confirm that assumption. In our replication of Tsimpli and Dimitrakopoulou’s study, we divide Spanish native speakers into those who accept resumptives and those who do not; then we look at their acceptance of gaps and resumptives in English. The results indicate that both groups of advanced learners, those that do and those that don’t have resumptives in their individual grammars, have acquired the ungrammaticality of resumptives in English, although there may be lingering native language effects. The effects of d-linking, animacy, syntactic function of the resumptive/gap (subject vs. object), and presence of the complementizer that are also examined.