The purposes of this article were to compare the characteristics of the vocal quality of therapists and patients in change and stuck episodes, and to depict patient-therapist interaction sequences of vocal properties, in order to analyze micro-regulatory processes within the psychotherapeutic interaction. Application of the Vocal Quality Patterns coding system to a study of a sample of change and stuck episodes, taken from six psychotherapies. The results made it possible to show that the 15 psychotherapeutic change process are embodied in the modes of vocal expression of their participants, and that the way in which these different modes are coordinated within the interaction makes it possible to observe regulatory micro-sequences that participate in the therapeutic change process.