The Effect of Substituting Discourse Markers on Their Role in Dialogue

There is general agreement that discourse markers help dialogue partners to highlight or locate available goal- or coherence-related information. There is, however, less agreement with regard to how the nature of the relation between the marked stretch of discourse and the rest of the dialogue should be defined. Recent work (Louwerse Mitchell, 2003) has used a substitution test to characterize the relation a discourse marker expresses. It is unclear, however, what the effects are of substitution on the suggested role of discourse markers. In this article, 7 experiments are reported. Four experiments examine the suggested role of discourse markers across a variety of topics, domains, languages, and media formats. The results indicate that discourse markers are helpful to localize the stretches of discourse that are believed to contain pragmatic information pertaining to discourse coherence and dialogue goals. Three experiments investigated the effect of the substitution of discourse markers on their suggested role. The results show that substitution has a differential effect on the localization and assessment of coherence and dialogue goals. Based on these results, it is recommended that care needs to be taken when substituting discourse markers because the functional relation between the marker and the marked stretch of dialogue could be compromised.