On Dissociating Discourse Salience from Information Structure: Evidence from a Centering Study on Modern Greek and Japanese

Eleni Miltsakaki (University of Pennsylvania)

In this paper we argue that determining the salience of a discourse
entity is a process orthogonal to information packaging. Information
packaging is a structuring of sentences motivated by the need to fit
linguistically conveyed information into the hearer's model of the
context of discourse (Vallduvi and Engdahl 1995). At the
intra-sentential level, we show that the basic update unit for
calculating salience is the sentence, defined as the main clause and
all the dependent subordinate clauses. The surface order of the main
and its subordinate clauses reflects only the information structure of
the sentence as a unit. Assuming that the preferred center of the main
clause is its subject, we claim that the higher ranked entity within a
subordinate structure does not override the salience status of the
higher ranked entity of the main clause, i.e. its subject.

We bring forth evidence from Modern Greek and Japanese. Modern Greek is a free w ord order language. However, we show that the surface word order is not the relevant factor in determining the preferred center of an utterance. We then present the results of applying the centering algorithm on a Modern Greek short story (6,000 words). The distribution of nominal and pronominal forms with respect to centering transitions indicates that contra Kameyama (1998), the subject of the main clause remains the preferred center independently of the subject of a subordinate structure and its surface position relative to the main clause.

In Japanese, subordinate clauses must precede main clauses. Null subjects are very commonly found in main clauses referring back to the subject of the previous main clause crucially skipping the subject of an intervening subordinate clause. Treating the intervening subordinate clauses as independent units in centering yields a highly incoherent Japanese discourse.