Babbling and the lack of auditory speech perception: a matter of coordination?

This paper concentrates on the question whether and where the lack of auditory perception can be traced in the early sound productions of deaf infants. A sensorimotor description system based on movements in the phonatory and articulatory speech production systems was developed to classify early infant vocalizations. Canonical babbling is a strong cue in the normal speech developmental process. Therefore the main question in this work was why deaf infants do not start to babble in their first year of life like normally hearing children do. Detailed analyses of early vocalizations of deaf and hearing infants revealed that auditory feedback is needed to lead to coordination of movements of the phonatory and the articulatory system, and that this coordination capacity is a prerequisite for the development of normal speech production.