How to learn a language

I found an interesting post through Technorati tagged Pimsleur about how to learn a language. And for once it actually seems quite sensible and plausible. It’s also made me think about grammar and how it should be handled in my language learning app. At the moment it plays the audio at you without anything on the screen. Perhaps the screen could display explanations of interesting or important points about what you hear? I’m worried about distracting people from listening and limiting the offline usability of precompiled lessons though… Pimsleur, polyglot