"First year or two"?
You're doing it wrong. The trick is to put your brain in a position where the only possible escape is to learn the new language, and learn it fast.
I made it clear to my room-mates/colleagues/acquaintances that I didn't want to fall back to any other language. They were really nice and patient, and were already laughing while I tried to make silly jokes with my 50 words vocabulary. I had some big headaches during the first month, and was exhausted every day after trying to make sense of the new language.
After about 2 months, I could speak well enough to make myself understood by anyone. I had a great time, and my social life was also helped because locals found it cute that I went through all this trouble.