Children's brains are simply different: they have innate abilities, which, I'm afraid, we lose as we grow up.
However, I do think we adults can learn from children - and make learning FUN at times. We forget the value of play, of games, of quizzes, of poems and rhymes, and, of course, songs.
How about getting a kiddies' book of nursery rhymes (good for pronunciation and fluency) then, after you've learnt the rhyme (very useful for when you have children of your own) you can dig into the origin of the rhyme. Researching the origins is real grown-up stuff. There are all sort of psychological and historical facets to any rhyme. Many rhymes have really nasty beginnings - The Black Death, for example.
Fascinating and scary stuff.