Final answer:
Children's ability to learn a new word with just one exposure is called fast mapping, reflecting their impressive cognitive capacities for language acquisition influenced by both innate biological predispositions and their linguistic environment.
Step-by-step explanation:
When children can learn a new word, sometimes with only one exposure, it is called fast mapping. Fast mapping is the term used to describe the process by which children rapidly connect a new word with its meaning, often after a single exposure to the word in context. This ability is a key component of language acquisition and demonstrates the remarkable cognitive abilities children have for understanding and organizing language.
It is part of the broader phenomenon of how children acquire language, tapping into their biological predisposition to learn and utilize language structures, a concept widely studied and proposed by figures such as Noam Chomsky.