I speak about four languages from fluent to quite good. And unfortunately I cannot give you the answer. With me, and many others I think, it just goes automatically. You dont have to do anything special apart from just make a whole lot of effort to learn those languages. I never confuse any of the four languages I am quite good in.

Okay..Sometimes, I confuse French, in which I am actually not that good, with Spanish, which I know really well. But I think that is because my Spanish is a whole lot better than my French. I never confuse for example English, German and Spanish.

So just go and do your homework, there is no magic method, apart from working hard.

When you become fluent enough, you don't have to think how to "switch" from 1 language to another. It happens naturally. However, when you speak 1 language for several days, weeks or months, and you suddenly have to start using another, it may take a couple of days or so to stop mixing them together. Especially if you know them equally well.

I speak five languages. Irish and English fluently, French and ISL decently, and beginners' Chinese. 

You have to practice speaking in each language. I have spoken Irish and English since I was a little girl, so that process is automatic. In French it was necessary for me to write down paragraphs and practice reading them outloud, as well as watching French TV. For ISL it was necessary for me to spend time talking with groups of deaf people, as well as creating paragraphs for myself to sign. I am still very slow with Chinese, but again, practice!

Watching TV helps because you are relying on visual images to understand what is being said. You pick things up naturally, learning the same way you would as a child. I strongly recommend it. And as people above have mentioned, <em>practice is vital. </em>

Correction:

If you speak more than language, how can you programme your mind to speak without thinking in the other one ?

<em>If you speak more than one language, how can you programme your mind to speak and think in one without thinking in the other?</em>

It can be automatically ! I mean if you are advanced in some languages , it's quite easy to speak correctly , but if you learn many languages at the same time and you are in the beginning for sure you will mix thing together ! That happened with me when i start to l

earn English and korean at the same time ^^

Hi,

when you learn a language don't stay satisfied by only vocabualary of that language ,Vocabulary is necessary in first level .

But in second level to master a language you have tolearn a hole expression, many expressions just know how we use them and when we use them because some expression are availible in a language and not availible in the other language and if you translate it literally it is gone be a really wrong,

You have to get in the heart of that language, by entring in theire culture and being one of them and forgeting who you are for only just a moment imagine it like having  two or more distinct identities or personality states ;).