this paper is that neither has been implemented." ([Vaughan and McDonald, 1986], page 95). Although Meteer [1990] gives a detail description of the relationship between text structure and revision it is unclear how the proposed model could contribute to the choice problem of paraphrases (see section 5.2). How- ever, from the approach described above and from the system described in [Meteer, 1990] we can draw the following conclusions. Only the generatoFs input is marked. If the generator encounters alternative realizations the revision component is asked to make the decision. However, to be able to do this it needs detailed knowledge about the grammar. Therefore grammatical knowledge has to be duplicated. The linguistic realization component used in [Meteer, 1990] is MUMBLE-86 [McDonald, 1986]. The text structural representation level must completely specify the infor- mation to be expressed by the utterance. The mapping has to ensure that all the necessary linguistic information is present. Mumblers procedural grammar is used only for generation purposes. Therefore it is without reach for the revision model to take into account relevant sources of ambiguities

We describe a method and its implementation for self-monitoring during natural language generation. In situations of communication where the generation of ambiguous utterances should be avoideel our method is able to compute an unambiguous utterance for a given seenantic input. The proposed method is based on a very strict integration of parsing and generation. During the monitored generation step, a previously generated (possibly) ambiguous utterance is parsed and the obtained alternative derivation trees are used as a 'guide' for re-generating the utterance. To achieve such an integrated approach the un derlying grammar must be reversehie.