One son, Sweetie, plunges into subjects and learns them by total immersion. For instance, he wanted to learn piano so he taught himself the "Moonlight Sonata", only occasionally asking his dad or me for direction on the notes. Then his next was Grieg's "Piano Concerto in A Minor" which is loud and complicated and all over the key board. I look at a piece and if it has too many sharps and flats, I move on to something else. Not him. He sits and the piano and pounds it out, over and over and over and over until he owns it.
He did this with Tolkien, Star Wars, Hockey. He focuses his attention on an area, sucks the very essence out of the subject, then decides he's finished and moves on. I wonder if there is enough music in the world to keep this interest going for some time.
This is the son who is studying Greek for fun.