Children’s acquisition of language is an amazing feat. Children master the syntax, the sentence structure of their language, through exposure and interaction with caregivers and others but, notably, with no formal tuition. How children come to be in command of the syntax of their language has been a topic of vigorous debate since Chomsky argued against Skinner’s claim that language is ‘verbal behavior.’ Chomsky argued that knowledge of language cannot be learned through experience alone but is guided by a genetic component. This language component, known as ‘Universal Grammar,’ is composed of abstract linguistic knowledge and a computational system that is special to language. The computational mechanisms of Universal Grammar give even young children the capacity to form hierarchical syntactic representations for the sentences they hear and produce. The abstract knowledge of language guides children’s hypotheses as they interact with the language input in their environment, ensuring they progress toward the adult grammar. An alternative school of thought denies the existence of a dedicated language component, arguing that knowledge of syntax is learned entirely through interactions with speakers of the language. Such ‘usage-based’ linguistic theories assume that language learning employs the same learning mechanisms that are used by other cognitive systems. Usage-based accounts of language development view children’s earliest productions as rote-learned phrases that lack internal structure. Knowledge of linguistic structure emerges gradually and in a piecemeal fashion, with frequency playing a large role in the order of emergence for different syntactic structures.
