Principles of speaker characterisation Main responsibility for the research area: TeknD Mats Blomberg Speaker characterization is a domain of knowledge of critical importance to a number of speech technology applications. It is a known fact that human beings are very skilled at recognizing speakers, and that they adapt rapidly to the individual or dialectal pronunciation of different speakers. As of yet, no corresponding technical methodology exists for characterizing speakers based on brief utterances. Instead, what is often used is a statistical description that models a whole group of speakers. In such a process, individual differences between speakers are reduced, which decreases the accuracy of decisions. There is a need to reduce the amount of speech data for speaker adaptation. For this purpose, techniques for fast adaptation based on speaker characteristic features will be investigated. The adaptation techniques can also be used for adjustment of synthetic speech to individual natural voices. A variant of using speaker characterization for speech recognition is to exploit speaker coherence, the fact that the speaker remains the same throughout the utterance, something that is not done in standard HMM systems. During the past few years, speaker verification has attracted a substantially increased amount of attention. One reason is the predicted increase in speech recognition-based personal services over the telephone, where speaker verification can become an important component in security. The reading aloud of, e.g., electronic mail and bank account information over the telephone also requires security, to prevent the information from being accessed or delivered by an intruder. In such cases, the speaker's voice is already available to be used also for identity verification. Important Research Topics for Stage 3 improvements of methods for speaker verification over the telephone develop methods for fast speaker adaptation and utilisation of speaker coherence