1. A system for adapting the user interface in systems that: accept speech input and perform automatic speech recognition (ASR), comprising means for receiving .an utterance; means for processing said utterance using ASR to generate an interpretation of said utterance and to determine a level of confidence in said interpretation; and means for selectively adapting the verification of said interpretation requested from the user as a function of said confidence level, wherein said system further includes means for storing, for each user of said system, information representing a success measure computed as a function of previous uses of said system, and means for retrieving information from said storing means and for adapting said user interface as a function of the value of said success measure.