Abstract: A common problem faced by speech dialog systems is that they have to serve users with varying degrees of experience of such a system in an optimal manner. The invention relates to a speech dialog system that differentiates between inexperienced and experienced users and generates speech prompts that are adapted accordingly. The system is able to differentiate between inexperienced and experienced users, issuing a detailed speech prompt to the former and an abbreviated speech prompt to the latter. According to the invention, the speech dialog system initialises a dialog step using an abbreviated speech prompt. If the system user does not react to the abbreviated speech prompt after a specified time (recognition timeout), a detailed speech prompt is issued. Thus both types of speech prompts are issued for each dialog step and are available to the system user for selection. The user can therefore always select the type and manner of dialog he or she requires.

Abstract: In a process for operating a speech dialog system, which adapts its to the speech quality of different speakers, the speech recognizer estimates the probability of a correct recognition of the user response or expression, in that it consults for estimation a confidence gage by means of which the words or phrases potentially contained in the speech response or expression are assigned a confidence value. One of the particularly preferred solutions of the inventive task are comprised in that for those speakers which are difficult for the speech dialog system to understand, it accepts in certain cases repetitions of the same user responses which, by themselves, would not be acceptable. A further advantageous solution is comprised therein, that the confidence threshold is selected depending upon the actual current dialog step.