What are reasonable expectations for linguistic theories of dialogue?
Under that there are several aspects worth focusing on. The focus of this memo is simply numerosity. At what level should we expect single theories in competition, rather than multiple theories in collaboration? Whatever level we choose, the single theories at that level must • Cover the entirety of some identifiable scope, and • Combine to cover larger scopes of phenomena. Unfortunately, without having a consensus on the nature of dialogue or diverse natures of types of dialogue, we do not have a range of levels in the sense used above. Another way to address the same issue is to ask what the phenomena being addressed depend on. If we have a dependency, say, of interpretive outcomes what text means on particular lexical items in particular languages, then we expect to require a distinct version of the theory of that phenomenon for each language. Some phenomena appear to be language independent. It is quite plausible, for example, that the qualitative basis of coherence of dialogue is
