Modelling caregiver tutored development of pronunciation in a young child

Authors: Ian S. Howard, Piers Messum

Abstract:

Imitation is almost always assumed to be the mechanism by which infants learn to pronounce speech sounds, which are the elements from which words are made up. Specifically, it is believed that auditory matching enables a child to reproduce speech sounds by copying those that he hears. For several reasons, we believe that this is not the way that this systemic aspect of pronunciation is acquired. We test an alternative account involving a non-imitative mechanism using Elija, a computational model of an infant. Elija started by learning to babble in an unsupervised fashion. Three separate experiments were then run with Elija using one native speaker of English, French and German to play the role of the caregiver. Each caregiver interacted with a different instance of Elija in his or her native language. Using the tutored interactions from each caregiver, which involved their reformulations of his putative speech sounds, Elija learned (1) the importance of his productions, and (2) the correspondence between his and adult speech tokens, thereby developing an ability to imitate a series of such tokens, that is, a word. Finally, using his newly acquired ability to parse input speech sounds in terms of the equivalents to his own tokens, each caregiver taught Elija to say some simple words by serial imitation. We present results from these experiments and discuss the implications of this work.