The findings could help explain why cultural immersion is the most effective way to learn a foreign tongue and why immigrants who settle within an ethnic enclave acculturate more slowly than those who surround themselves with friends from their new country."
And this needed a study? Well, I where I come from, our samll country has over 66 tribes; each one of them with a different language and custom. Guess what; I fluently speak 11 of those with no difficulty at all.
I even speak English better than those who have it as their first language (grammarvwise). I also learnt German, Mandarin and Spanish faster than any students in my class. As a result, I got the reward[s] of mingling with the fairer gender easily (and reaped the rewards!!), while fellow students from the so called 1st world were grassing. No neeed for a study here. It is obvious.