From a user’s perspective, biometric systems perform a conceptually simple task: recognition of persons. However, their implementation is generally highly complex. The general approach involves the enrolment of a person in the system and the learning of a biometric model. At the time of use, a new biometric sample is compared to the model. The biometric system will then decide if the new sample is sufficiently close to the model in order to confirm (or not) the person’s identity. In the case of speech, the biometric model is sometimes referred to as a voiceprint.