Correlates, yes. But one of the best students I've met, who in a mock visa interview answered the question "it costs a lot of money to live in America. Can you afford it?" with "we have a hundred million RMB", was basically unable to function in conversation. (In the same interview, which was meant to be conducted in English, more than three quarters of her responses were just "什么意思？".)

Some people aren't interested in learning languages. Some people have tremendous difficulty.