Imitation is one of the major processes by which humans develop social interactions. In speech communication, imitative processes are used from birth to adulthood, as highlighted by children’s mimicking abilities and by adult’s tendency to automatically “imitate” a number of acoustic-phonetic characteristics in another speaker’s speech. These adaptive changes are thought to play a key role in speech development/acquisition and to facilitate conversational exchange by contributing to setting a common perceptuo-motor link between speakers. Based on acoustic analyses of speech production in various laboratory tasks, the present study aimed to better characterize sensory-to-motor adaptive processes involved in unintentional as well as voluntary speech imitation, and to test possible motor plastic changes due to auditory-motor recalibration mechanisms.