I Bet This Works:

I bet this works: learn a foreign language by reading Harry Potter in translation (link).

Fact is, I'm almost certain it works. Or more precisely: I have a supremo edition of Herodotus’ Histories in classical Greek, with Italian on the facing pages. Pardon, that is Erodoto, Le Storie—it is the one with the splendid introduction by David Asheri, best general intro to Herodotus that I ever saw. I figure that even if I can’t read the Greek (often), at least I can make out the Italian (sometimes).

My only hesitancy is that I haven’t read Harry Potter (yet) in English.

Fn.: Years ago I met a guy who had taken a class in Gothic. Apparently the only significant Gothic text is the (incomplete) New Testament, so the students had worked with a facing-pages text: Greek on one side, Gothic on the other. When they got stumped on the Gothic, the professor would say “Read the Greek! Read the Greek!”

Hat Tip: Kottke.