And again I say it - it's not that we're better at learning when we're young; it's that when we're young - "c'est son métier", as Heinrich Heine said of God (asked on his deathbed if God would forgive him all his great sins, he reputedly answered "Of course He will, it's his job!"

Children spend all their time learning - it's their job. They learn new words, new concepts, new behaviours, what's correct and what's not and what they can get away with, how to charm people when they need to get away with it, they learn songs and skipping rhymes and games and dances and ball-hopping routines and playing jacks and cards. Their whole life is learning. So they have lots of practice.

The reason adults can find it more difficult is not anything inherent - it's that we're out of practice. Once you get back in practice, you learn very, very fast, which is why I say to try Duolingo, which will give you daily practice in a new (or old) language, and seamlessly slide words and concepts into your mind. Once you get back in practice, you'll learn as fast as a child, or faster.