Your brother's speed is quite interesting. Could you let us know how many hours he spend learning a new language in a day to acquire that many words?
Also, I wonder if he needs to be in an immersive context for that rate to be sustained.
Also, I wonder if he needs to be in an immersive context for that rate to be sustained.
He was learning Japanese while living in Canada, so I'm pretty sure that he doesn't need an immersive context for that rate. However I doubt he could pick up on the finer nuances without being in an immersive context.