can I say: Most of the Chinese in USA only "get together with" the Chinese?
can I say: Most of the Chinese in USA only "get together with" the Chinese,
so some of them don't speak English.
Does the phrase get together works in the sentence?
or is there any other better word to phrase "get together?"
I used to learn a phrase for the meaning but i forget :(
Hope I can get the phrase again from here:)

Question

can I say: Most of the Chinese in USA only "get together with" the Chinese?
can I say: Most of the Chinese in USA only "get together with" the Chinese, 
so some of them don't speak English.
Does the phrase get together works in the sentence?
or is there any other better word to phrase "get together?"
I used to learn a phrase for the meaning but i forget :( 
Hope I can get the phrase again from here:)

Answer

Yes, I'd agree that 'associate with' is the best phrase here.

Or you could say 'socialise with' (US spelling - socialize) if you mean that they might work or study with non-Chinese people, but spend their leisure time with other Chinese.

Answer

'the USA' and 'other Chinese' - but apart from that, it sounds fine to me.

Answer

"Most Chinese people in the USA associate only with other Chinese, so some of them don't speak English."

You might have been thinking of "hang out" but I'd avoid phrasal verbs in this context.