It's just twice as much study. That is all.

As for me, I grew up speaking Filipino (Tagalog) and English at the same time. Listening to my mom speaking in Japanese (she can speak it) made me a bit fluent in Japanese (as in a BIT) and I am teaching myself on how to speak Korean as well. I believe it is easy but it would be hard if you cannot concentrate on one language at a time. So Ms. Ayab257 is right. Don't compare the languages that you want to learn. If you are now learning English, just focus your entire mind in English. If you are learning Japanese, do the same. Don't translate a sentence from your native tongue to Japanese for example. It would only make things more complicated. If you're in a Japanese mode, try to think of Japanese only and not of any language. :)

I grew up speaking Arabic, Hebrew and English. So I don't think that is the same as learning two languages at an older age in the same time. It is hard, and you must not compare the two languages you are trying to learn, it can get rather confusing. Best advice I can think of is learn each at a time, don't mix both (regarding grammar). You can learn vocabulary simultaneously (How do you say the same word in both languages).

I think it's difficult enough to learn one language, and agree with 雲小泉 that trying to master a second language at the same time is too much. I think it's better to dedicate all your available study time and energy to perfecting the first language as much as possible, before taking on a second language. Of course, if you only want a superficial knowledge of either language, then there's no problem. But if you want to become conversant in both language, you have a lot of work and confusion ahead of you. I started studying Russian in January, and I'm very happy with my progress, but it took a lot of practice and effort. I couldn't imagine dedicating that much to a second language with any measurable success.

Hi! What do you think about LEARNING two or more languages at the same time? Is it difficult? I've saw that many people know two or three languages and study a third, forth, or fifth one here. Guys, how did you do that?? )) I'M learnING English and want to learn French and Japanese ALSO. Can you give me SOME advice about LEARNING a few languages at same time? Thanks)