How to say in Czech: Are they learning Polish on their own?

English
Are learning on their own?
Czech
Oni se učí polsky jako samouk?
Are they learning Polish?
They are learning Polish.
Where did they learn Polish?
How good is their Polish?
Their native language is Polish.
Their Polish is getting better.
Their Polish is very good.
Are they Polish?
They are not Polish.
They are Polish.

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