... plans actions to satisfy an agent's goals, but allows some of the actions to consist of the utterance of sentences. This approach to language generation emphasizes the view of language ... only to observing the speaker's actions. The reader may wonder if an SI action can be regarded as a degenerate case of the NSI action. In the case of the NSI action, the speaker and hearer ... because there is no plan the hearer can formu- late to take advantage of the description. An example of such a nonuseful description would be if S and H are riding a bus, H asks at what stop...