Any speaker classification or recognition system functions in 3 modes:
Naturally, a given speaker cannot be identified or verified in the test mode before he has been registered during a training phase . However, training is usually incremental in several ways. Firstly, a speaker recognition system is usually operational before all possible speakers are referenced, and new users can be added while the system is already functioning in test mode for those who are registered. Secondly, some system implementations use speech material obtained during a test phase to update training references (when the recognition decision is judged reliable enough).
Unlike training and testing , untraining does usually not require active participation of the speaker being unregistered.