According to this video, I could have learnt a new language:
See Fluent in 3 months
Whilst this is an enormous claim, it sounds like it could be like a 21st century L.A.M.P. We used LAMP to learn Spanish over a year, and I it really works because the goal is communication, so you start talking to real people about real things from day one.
Having said that I take my hat off to people we visited in Asia who are learning a language that has tones and doesn't use Roman script. To not only talk, but read and write that takes years - a real commitment from people who want to contribute long-term to a group of people.
Have you learnt a new language? Do you have any language hacking tips?