Final answer:
The easiest time to learn a second language is in early childhood, due to biological predispositions and a critical period for language acquisition. Babies and toddlers learn language effectively through mere exposure, with this ability gradually decreasing as they age.
Step-by-step explanation:
The easiest time to learn a second language is generally in early childhood. During this developmental stage, children exhibit a remarkable capacity for language acquisition, which is believed to be due to both biological predispositions and cognitive abilities specifically attuned to learning language. Researchers, including Noam Chomsky, assert that children are born with an innate capacity for language learning, equipped with a language acquisition device. This period of heightened language learning capability is often referred to as the 'critical period,' which suggests that as a person ages, the facility to master new languages diminishes.
Babies and toddlers acquire language skills by simply being exposed to the language in their environment without formal instruction. This natural propensity to absorb and understand complex linguistic structures is most potent during early childhood and gradually wanes with age. Although individual results can vary, and some adults can also become proficient in a second language, the consensus in cognitive psychology points to early childhood as the optimal time for second language learning.