In this paper we present our experiences in developing a spoken dialogue system supported by tests with a user simulation. Since the code of dialogue systems with modest complexity can easily get unclear, it is almost impossible to deliver error-free systems without user tests in the development process. We show how we included our user simulation environment SpeechEval in the development process of three VoiceXML dialogue systems and discuss advantages and drawbacks compared to tests with real users.
Index Terms: spoken dialogue systems, user simulation, user tests