Mastering is impossible. French is my native language for 38 years and I wouldn't never master it, because there is always new words, new rules I escape... You could just try to reach the perfection, but not to "master" a language or to be perfect on it. We must admit we are just human beings.

Would you like to spot and correct the deliberate mistake in your question, Mr. Teacher?

Hello! you can read the opinions of others here. They have ideas to share. Read it and be motivated to learn other language.

I think at least 3 years to know a lot of words and to start to speak without being shy to speak a foreign language cause you afraid to say some thing wrong but..... if i live with native speakers i think i will not take a lot of time to be perfect and to speak fluent too

I've been studing English for 2 years. And I think, I have smth middle between Pre-Intermediate and Intermediate levels.