In many languages, subjects are much more difficult to extract from embedded clauses than objects. In English, subject extraction from that-clauses appears to be prohibited:
Interestingly, German and Dutch do not appear to have such a constraint and subject extraction from embedded complementizer clauses is relatively unproblematic. In my current research I investigate whether there really is no subject/object asymmetry in German and Dutch and if so, why this is the case. The ultimate goal is to find out which constraints are at work when long-distance subject dependencies are created.
I also work on intervention effects, specifically negative intervention and case-intervention. Intervention effects are associated with degraded acceptability and/or an increased processing load. They arise when an intervenor ‘intervenes’ within a dependency (such as a dependency created by movement). My current work includes research on negative intervention and case-intervention.