Modeling Early Vocal Development Through Infant–Caregiver Interaction: A Review

The developmental origin of language communication seems to involve vocal interactions between an infant and a caregiver, and one of the big mysteries related to this is how an infant learns to vocalize the caregiver's native language. Many theories attempt to explain this ability of infant as imitation based on acoustic matching. However, the acoustic qualities of speech produced by the infant and caregiver are quite different and therefore cannot be fully explained by imitation. Instead, the interaction itself may have an important role to play, but the mechanism is still unclear. In this paper, we review studies addressing this topic based on explicit interaction mechanisms using computer simulations and/or real vocal robots. The relationships between these approaches are analyzed after a brief review of the early development of an infant's speech perception and articulation based on observational studies in developmental psychology and a few neuroscientific imaging studies. Finally, future issues related to real infant-caregiver vocal interaction are outlined.