It is hard for introverts to explain situations, especially those naturally taciturn. They have the loudest minds, act little, and prefer to be left alone. I know a friend back in school who talks very little. It seemed he counted his words, and one day, a classmate lied against him. He was punished for what he didn’t commit. Why? He couldn’t explain himself!
I have some introverted friends; they can be very creative, unique, and intelligent.

So it is nice to allow people (friends, peers, colleagues, partners, wives, husbands, kids) to be themselves.
We may not be able to discern why people act the way they do or choose to be alone. If you find someone who doesn’t like talking much, help by giving them some space. Usually, such people have their time to talk. Be patient and move with their flow.