mneumonic devices. 'memory palace' techniques. Currently learning spanish using this and it is pretty absurdly effective. Definitely couldn't do 40k words in 9 weeks, but obviously im a rank novice and this dude is a pro. But yeah I've memorized probably 2k words, their meanings, and their idiomatic usages in about 90 days using a program called learncraft spanish that uses mneumonic devices.