Quiet not speaking a lot на английском языке:

He is reticent and he never speaks unless spoken to.

Paweł is a very reticent man.

But she has been reticent when it comes to sharing them.

I personally think that the only reason for her failing the oral exam was her reticent nature.

She's strangely reticent about her son.

they were reticent about answering questions

she was extremely reticent about her personal affairs

He is very reticent about his past.