New article: How to learn a language quickly
You might find this interesting, or even helpful for the future development of Duolingo.
Focus: How to Learn a Language Quickly
It's an interesting article, but I just have to share that dogs can learn the same way. http://www.youtube.com/watch?v=wnb0D_aKz-U I used to have an Australian Cattle Dog (second in intelligence to Border Collie) and each of his toys had a name although he didn't have a thousand toys and he could do the same thing with a new toy's name.
Can't get at the original article, but it does seem that they've proved that acquiring a typical adult vocabulary would be impossible without the mutual exclusivity strategy (unless you could find something similarly powerful with which to replace it). Interesting cognitive linguistic result, but I'm not sure how much direct application it has to post-childhood second language acquisition -- you don't really need to rely on mutual exclusivity so much when you have a bilingual dictionary!