Principles that are overlooked when people try to learn foreign languages

Chris Lonsdale has produced one of the best reviews I know of why so many aspiring foreign language learners end up frustrated. There are a lot of electronic courses and apps out there, but how many are based on sound principles?

Chris Lonsdale at TED

Technology in language learning is good if it is used intelligently, ie in accordance with demonstrated principles of what really works.  Otherwise low-tech is just as good.