How to say in Czech: Is he learning Vietnamese?

English
Is learning
Czech
Učí se vietnamsky?
He is learning Vietnamese.
Is he learning Vietnamese on his own?
Where did he learn Vietnamese?
Does he speak Vietnamese?
He does not speak Vietnamese.
He does not speak Vietnamese very well.
He speaks only a little Vietnamese.
He speaks Vietnamese.
He speaks Vietnamese fluently.
He speaks Vietnamese very well.

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