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

English
Is learning on his own?
Czech
On se učí portugalsky jako samouk?
He is learning Portuguese.
Is he learning Portuguese?
Where did he learn Portuguese?
His native language is Portuguese.
His Portuguese is getting better.
His Portuguese is very good.
How good is his Portuguese?
Does he speak Portuguese?
He does not speak Portuguese.
He does not speak Portuguese very well.

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