Final answer:
A child could learn to say "not" by first imitating parents, then through operant conditioning when they use it correctly and are understood or approved, and finally due to the innate language acquisition device proposed by Chomsky that all children possess.
Step-by-step explanation:
Constructing a plausible scenario where a child learns to correctly say "not" involves understanding the complex interplay of imitation, operant conditioning, exposure, and innate language acquisition abilities. For instance, a child might first hear the word "not" used frequently by their parents and start to imitate its usage. Later on, the child might use the term in context and receive positive reinforcement, such as approval or being understood, thereby learning the word through operant conditioning. This reinforcement can accelerate the integration of the word into their vocabulary. Additionally, while a single exposure to the word in a book is less likely to result in immediate mastery, it's plausible that this exposure, combined with reinforcement and the innate language acquisition mechanisms that children are born with as proposed by Noam Chomsky, leads to the child incorporating "not" into their language usage.