I agree. The human brain gets formed in certain way before you are 5 (sorry, I don't recall the exact terminology or age). As they say Chinese is easy, in China

I agree. The human brain gets formed in certain way before you are 5 (sorry, I don't recall the exact terminology or age). As they say Chinese is easy, in China even small kids speak it. (Chinese readers, please subsitute by another, "difficult" language.) Later it gets more difficult to learn any other language. But of course closely related languages are always easier than some fundamentally different language. I speak 5 languages and my factor is up to 12. It took me months to reach certain proficiency in a language close to my mother tongue, but the same number of years in another language, which is very different. From my fellow students in language classes I have seen it can be the opposite for them depending on their mother tongue. Cultural impact is big. In some small countries where movies are not dubbed (say Iceland) young people speak English much better than in bigger countries where no such influence exists (France, Italy). Americans are particularly bad in foreign languages. I don't think it has anything to do with languages as such, it's a cultural issue. It's not considered important, because a lot of information and entertainment is available already in English.