Learning to speak involves control of the oro-­‐facial articulators, as well as the construction of relationships between motor commands and auditory and somatosensory sensations. The main goal of this study is to further investigate the hypothesis that differences in speech production between children and adults can be explained on the basis of speech motor control maturity. With this aim, we have designed a speech production study focused on two indices: token-­‐to-­‐token variability in the production of isolated vowels, and extra-­‐syllabic anticipatory coarticulation within V1-­ C-­‐V2 sequences. Token-­‐to-­‐token variability reflects the maturation of speech motor control in terms of motor patterns for the production of a given target speech sound. In line with theories of optimal motor control, anticipatory coarticulationis assumed to be based on the use of internal models, i.e. sensorimotor representations of speech sounds, and the amplitude of anticipatory coarticulation is presumed to reflect the increasing maturation of these sensorimotor representations as speech develops. Our hypothesis is that the neural representations of the speech motor systemsof four-­‐year-­‐old children are immature, particularly in their inability to account for the appropriate variability compatible with correct perception of the target sound, leading to a lack of effectiveness in anticipating forthcoming gestures.