Case Constraints and Empty Categories in Optimality Theory Parsing

Double object questions are harder to process than the corresponding questions with prepositional objects (Boland 1997). When given the choice between the two, a parser prefers to wait and not associate a filler with a gap in a double object construction, contrary to the prediction of the Active Filler Hypothesis (Frazier 1987). I propose that the reason the parser holds back is that it wants to avoid a structure that has dative Case; this pressure is stronger than the pressure to associate a filler with a gap, which comes from the thematic requirements of elements in the sentence (and not from the cost of holding the filler in memory). The results are formulated in an extension to Stevenson and Smolensky’s (1997) Optimality Theory parser, as tension between constraints that mark Case and argument structure.