[B]rain cells activated by an experience keep one another on biological speed-dial, like a group of people joined in common witness of some striking event. Call on one and word quickly goes out to the larger network of cells, each apparently adding some detail, sight, sound, smell. The brain appears to retain a memory by growing thicker, or more efficient, communication lines between these cells.My approach to language learning has always been one of multiple types of exposure. Take a new vocab word, for example. Let's say you come across it in a book. You've now got speed dial set up between that book and the word, and perhaps between the word and the sentence, paragraph, thing it was in reference to, etc. Then you look it up. Now you've got the connections built to the meaning. Let's say you later hear it in a podcast. There's another connection. An example like this would seem to fit into the paradigm they suggest: you're building thicker connections to that word, and are thus more likely to learn it. Apply that to all units of language learning—words, phrases, grammar rules, characters, pronunciation, intonation, etc.—and you can see how various exposure makes language learning easier.
A quick look at the ethical issues, and a clip from The Matrix,after the jump.