Over the past 20 years, the topic of discourse markers (DMs), alternatively "discourse connectives," or "cue phrases," illustrated in bold type in (1), has been the subject of considerable research, both theoretical and descriptive.

(1) a) He came. However, he didn’t stay.

b) I like Mary because she doesn’t whine.

c) Where are you going. And what are you going to do when you get there?

d) It was raining. Moreover, the beer was cold.

e) He was forced to work overtime so he up and quit.

f) That has three wheels. Thus, it can’t be a bicycle.

During this period, researchers from at least six distinct theoretical positions have focused on the theoretical status of DMs. The research paradigms, listed alphabetically along with one researcher associated with each, are as follows: Argumentation Theory (Ducrot); Cognitive Theory (Sweetser); Coherence Theory (Sanders); Discourse Theory (Schiffrin); Linguistic Theory (Fraser); and Relevance Theory (Blakemore).

Because of the different paradigms within which the research has been carried out, the analysis and conclusions, predictably, have differed, sometimes widely. For example, Schiffrin argues that the effect of DMs is felt on five levels, not all linguistic, while Sweetser argues the effect is on three linguistic levels, and Blakemore is silent on the issue. For Schiffrin, some DMs have conceptual meaning, some do not, while for Blakemore and Fraser, they all have a procedural rather than conceptual meaning. And, while Blakemore sees DMs as guiding the hearer more quickly and accurately to implicatures of the utterance to which they are attached, Sanders treats them as expressions which reflect and thereby make precise the coherence relations in the text.

The present paper has two purposes: (1) to provide a comparative analysis of research results from the six paradigms, looking both at the differences and at the similarities; (2) to attempt to resolve the real and apparent differences found with a view to characterizing what DMs are and what role they play in discourse. Where this resolution is not possible, I will point out the incompatible assumptions that lead to this lack of harmony.