Automatic retraining of a speech recognizer during its normal operation in conjunction with an electronic device responsive to the speech recognizer is addressed. In this retraining, stored trained models are retrained on the basis of recognized user utterances. Feature vectors, model state transitions, and tentative recognition results are stored upon processing and evaluation of speech samples of the user utterances. A reliable transcript is determined for later adaptation of a speech model, in dependence upon the user's successive behavior when interacting with the speech recognizer and the electronic device. For example, in a name dialing process, such a behavior can be manual or voice re-dialing of the same number or dialing of a different phone number, immediately aborting an established communication, or braking it after a short period of time. In dependence upon such a behavior, a transcript is select in correspondence to a user's first utterance or in correspondence to a user's second utterance, or both, or the tentative recognition result (or results) are determined to be uncertain and deemed not to be suitable for updating a model, or updating is performed with appropriate weighting to take into effect the level of uncertainty. Upon determination of a reliable transcript, a model adaptation is performed.