During the development of speech-based database enquiry systems for dialogue over the telephone with members of the general public, Wizard of Oz simulations (in which an accomplice plays the role of the system) were conducted. The simulations provided evidence of naive callers adapting their speech to the system's presumed capabilities. They have also shown that callers tolerate speech recognition errors where there is graceful error recovery. However, the data have raised questions about the need for constraints to be imposed on callers' initial utterances if dialogues are to be successful.
Keywords: Simulation, Wizard of Oz, spoken dialogue systems.