Children's Development of Self-Regulation in Speech Production

Species-specific vocalizations fall into two broad categories: those that emerge during maturation, independent of experience, and those that depend on early life interactions with conspecifics. Human language and the communication systems of a small number of other species, including songbirds, fall into this latter class of vocal learning. Self-monitoring has been assumed to play an important role in the vocal learning of speech [1-3] and studies demonstrate that perception of your own voice is crucial for both the development and lifelong maintenance of vocalizations in humans and songbirds [4-8]. Experimental modifications of auditory feedback can also change vocalizations in both humans and songbirds [9-13]. However, with the exception of large manipulations of timing [14, 15], no study to date has ever directly examined the use of auditory feedback in speech production under the age of 4. Here we use a real-time formant perturbation task [16] to compare the response of toddlers, children, and adults to altered feedback. Children and adults reacted to this manipulation by changing their vowels in a direction opposite to the perturbation. Surprisingly, toddlers' speech didn't change in response to altered feedback, suggesting that long-held assumptions regarding the role of self-perception in articulatory development need to be reconsidered.