Final answer:
The main difference between babies and adults in language learning is that adults face more challenges learning a new language than babies due to a decrease in language acquisition proficiency with age. Babies, conversely, are naturally disposed to learn any language and can initially distinguish between all phonemes.
Step-by-step explanation:
In what way are babies and adults different regarding language learning? The correct answer is: a) Adults have a harder time learning a new language than babies. This difference is primarily due to the remarkable capacity babies have for language acquisition. Language proficiency in babies is facilitated by their biological predisposition to learn language, with cognitive abilities specifically attuned to absorbing and understanding language from a very early age. This includes the ability to distinguish between all possible phonemes in human language initially, a capacity that narrows to the ones present in their environment by around one year of age.
Adults, on the other hand, generally find it more challenging to learn a new language due to the decrease in this proficiency over time. Though they can more easily distinguish between certain sounds (for instance, between 'L' and 'R' in languages where this distinction is relevant), they do not retain the extensive phoneme differentiation capabilities they had as babies. Furthermore, adults generally do not utilize 'motherese' — the simplified and exaggerated form of speech often used when speaking to infants — as a primary method of language learning, as they often rely on more sophisticated language learning tactics.