That research hasn't yet made the grade. You'll constantly find articles that state "some linguists" are doubting the Critical Period Hypothesis [1], just as yo

That research hasn't yet made the grade. You'll constantly find articles that state "some linguists" are doubting the Critical Period Hypothesis [1], just as you'll find doubts for many hypothesis, but it's quite well accepted within the linguistic field. And if you talk to people that have been deeply exposed to language acquisition, like "drzaiusapelord" above (and ignore the spirited Redditors who went to Japanese class a couple times), you'll find that it holds. Language is fascinating and with immersion and other techniques can get to 99%. But if you didn't hear it and speak it at 6, you'll never get it like a native speaker. Here's a great example: I worked in Berlin for a Jewish woman who moved to America when she was 5. She didn't speak any English, only German, at the time. When she came back to Germany at 15, she had to learn German from scratch (completely from scratch). She was 50 when I worked for her and her German was flawless, but my German friends said that she occasionally made the tiniest of mistakes which made it clear she wasn't a mother-tongue speaker. She didn't make such mistakes in English. [1] http://en.wikipedia.org/wiki/Critical_Period_Hypothesis http://en.wikipedia.org/wiki/Critical_Period_Hypothesis