There is no innate pre-programming for language learning at birth. Psychological data should be limited to that which is observable. All behavior is viewed as a response to stimuli. Behavior happens in an associative chain. Conditioning involves the strengthening of associations between a stimulus and a response through reinforcement.
Human language is a sophisticated response system acquired through operant conditioning.
Universal Grammar Theory posits the existence of a set of basic grammatical elements or fixed abstract principles that are common to all natural human languages and that predispose children to organize the input in certain ways. Hmm. . . Language is a species-specific, genetically determined capacity. Language learning is governed by biological mechanisms. Core grammar rules are thought to be relatively easier to acquire, in general, than peripheral rules.