Discourse Segment and Japanese Referring Expressions: Are These Bare NPs or Proper Names ?

Forms of Japanese referring expressions are mainly divided into four types: bare NPs, demonstrative NPs (i.e. either as determiner or as pronoun) and zero pronouns. Out of the four types of the referring expressions, bare NPs are the most common type as a subsequent mention and zero pronouns are used only in limited conditions. Based on the centering framework, the results suggest that the center of attention is maintained by the chain of NPs rather than zero pronouns, and the chain of NPs is correlated with the global focus of discourse coherence. There is no doubt that bare NPs mainly carry the topic entity and continue to be used both within the border of discourse segment and over the discourse segment boundaries, while the zero pronoun can carry the topic entity only in the limited context of discourse and is likely to discontinue within the discourse segment. This result is not fully explained by the existing anaphora resolution and it is difficult to predict the typical pattern of referential transitions in naturally occurring discourse. It is worth noting that the repetitive use of bare NPs tends to function as proper names in the Japanese spoken discourse.