  In sum: Skinner was mistaken on all counts. Language mastery is not  merely a matter of having a set of bare behavioral dispositions.  Instead, it involves intricate and detailed knowledge of the  properties of one's language. And language learning is not a matter  of being trained what to say. Instead, children learn language just  from hearing it spoken around them, and they learn it effortlessly,  rapidly, and without much in the way of overt instruction.