It should be clear that monitoring and revision involves more than the avoidance of ambiguities. [Levelt1989] discusses also monitoring on the conceptual level and monitoring with respect to social standards, lexical errors, loudness, precision and others. Obviously, our approach is restricted in the sense that no changes to the input logical form are made. If no alternative string can be generated then the planner has to decide whether to utter the ambiguous structure or to provide an alternative logical form.
During the process of generation of paraphrases it can happen that for some interpretations no unambiguous paraphrases can be produced. Of course, it is possible to provide the user only with the produced paraphrases. This is reasonable in the case that she can find a good candidate. But if she says e.g., `none of these' then the paraphrasing algorithm is of no help in this particular situation.
Meteer Meteer:90 makes a strict distinction between processes that can change decisions that operate on intermediate levels of representation (optimisations) and others that operate on produced text ( revisions). Our strategy is an example of revision. Optimisations are useful when changes have to be done during the initial generation process. For example, in [Finkler and Neumann1989, Neumann and Finkler1990] an incremental and parallel grammatical component is described that is able to handle under-specified input such that it detects and requests missing but necessary grammatical information.