Dialogue Acts, Synchronizing Units, and Anaphora Resolution

Abstract

In this paper, we present the results of a corpus analysis, and a model of anaphora resolution in spontaneous spoken dialogues. The main finding of our corpus analysis is that less than half the pronouns and demonstratives have NP antecedents in the preceding text; 22% have sentential antecedents and the remainder have no identifiable linguistic antecedents. As part of the corpus analysis we present the results of inter-annotat or agreement tests. These were carried out for the annotation of anaphor types and their antecedents, and for the segmentation of the dialogues into dialogue acts. The results of the inter-annotator agreement tests indicate that our classification method is reliable and that the annotated dialogues can be used as a standard against which to measure the performance of the anaphor resolution algorithm. The algorithm, based on Strube (1998), is capable of classifying pronouns and demonstratives, and co-indexing anaphors with NP and sentential antecedents. The domain from which potential antecedents for both individual and discourse-deictic anaphors can be elicited is defined in terms of dialogue acts. The dialogue segmentation method uses dialogue acts to form Synchronizing Units, which reflect the achievement of common ground (Stalnaker 1974, 1979). We show that predicate information, NP form, and dialogue structure can be successfully used in the resolution process.