How to say in Czech: Is he learning Russian on his own?

English
Is learning on his own?
Czech
On se učí rusky jako samouk?
He is learning Russian.
Is he learning Russian?
Where did he learn Russian?
His native language is Russian.
His Russian is getting better.
His Russian is very good.
How good is his Russian?
He is not Russian.
He is Russian.
Is he Russian?

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