Early explanations of language development rested heavily on the roles of modeling and reinforcement in learning language. Which
one of the following children's utterances casts doubt on the idea that modeling and reinforcement are sufficient to explain how children acquire language?
Although modeling, reinforcement, and feedback almost cer-tainly play some role in language development, early theoriesbased on such processes could not adequately account for thefact that most children acquire a very complex language sys-tem in a very short period, and with only limited guidancefrom adults.
