Final answer:
Nativists assert that language is acquired by normally developing humans before the critical period, thanks to innate biological mechanisms, and not solely through reinforcement and conditioning.
Step-by-step explanation:
Understanding Language Acquisition
Nativists like Noam Chomsky argue that all humans have an innate biological mechanism, often referred to as a Language Acquisition Device (LAD), which enables them to acquire language. This acquisition is thought to occur primarily before the end of a critical period in a child's development. According to this perspective, the capacity for language acquisition is hard-wired and unfolds naturally, given proper exposure to language. Contrary to Skinner's behaviorist theory that language is learned through reinforcement and conditioning, Chomsky emphasized the biological predisposition for language acquisition. Research supports a critical period for language learning, with proficiency diminishing as people age.
The process by which children acquire language includes understanding and generating language, from discerning their mother's voice to acquiring a complex system of grammar. Instances like the case of Genie, who learned language beyond the typical critical period, illustrate the remarkable potential for language acquisition, although her grammatical mastery was never fully developed, lending some support to the critical period hypothesis.
In summary, the correct answer to the student's question is B. before the critical period. Language acquisition is tied to biological capabilities that are maximized early in life, rather than relying solely on reinforcement and conditioning.