Integrating Syntactic and Prosodic Information for the Efficient   Detection of Empty Categories
  We describe a number of experiments that demonstrate the usefulness of prosodic information for a processing module which parses spoken utterances with a feature-based grammar employing empty categories. We show that by requiring certain prosodic properties from those positions in the input where the presence of an empty category has to be hypothesized, a derivation can be accomplished more efficiently. The approach has been implemented in the machine translation project VERBMOBIL and results in a significant reduction of the work-load for the parser. 
Anton Batliner, Anke Feldhaus, Stefan Geissler, Andreas Kiessling,   Tibor Kiss, Ralf Kompe, Elmar Noeth