Lexical Marking Of Discourse Relations - Some Experimental Findings

Both in written and in spoken language, discourse relations may or may not be signalled by lexical material. In this paper we present the results of two experiments which were intended to answer some questions concerning the relationship between discourse relations and their lexical markers. Assuming that, in any case, discourse relations are inferred by the addressee/interpreter, the question arises about what suggests to the speaker/writer the strategical decision of using rather than not using explicit signals , such as connectives or cue phrases. In order to answer this main question, the following subques-tions need to be answered: first, which role do discourse markers play in the task of reconstructing the discourse relation which was originally intended by the speaker/writer. Second, to what extent the lexical signalling of the relation is essential for the relation to be inferred. Third, whether there are coherence relations that are always lexically signalled and whether there are any that are never lexically signalled. Finally, if the different access that addressees have to the linguistic context in spoken and written language affects the kind of relations employed in the construction of text and/or in the realization of the relations. 1 Discourse Relations Discourse relations have been addressed by a number of different approaches for the purposes of text understanding , text analysis and text planning. This results not only in a difference in the theoretical interpretations of the concept, but also in a het-erogeneity among the actual sets of relations which are assumed to be psychologically and/or descriptively adequate. On the other hand, the various approaches show a considerable overlap in the individual relations adopted, thus suggesting a "commOn ground" shared by all approaches. For the aims of our research, rather than committing to one or another interpretation of discourse relations, we have abstracted from the various taxonomies three broad classes or types of relations, namely an additive type, a consequential type, and a contrastive type. These three classes are identified on the ground of the basic cognitive operation which is implied in the instanti-ation of a connection between adjacent segments of discourse. Additive relations share the common feature of implying some kind of similarity between the segments they relate. We conceive the notion of similarity in a broad sense, so that an additive relation is supposed to hotd when a) p(x) can be inferred from the assertion of $1 and p(y) can be inferred …