Is it bad if you talk little to no other than with your best friend?

I simply can't think of enough questions to keep asking. Maybe that's because of my illness. I have the feeling that people always expect me to ask or say something before me. I'm rarely asked anything first. Maybe other people feel the same way. At the day center, for example, I hardly ever talk to anyone else. I only talk a lot to my best friend, but not all the time. I have no idea why that is. Maybe it's just me being shy or having an inability to communicate. But it always takes at least two people to talk. I'm actually very introverted and literally the epitome of calm.

A former colleague could be my sister, who's just the same, very introverted. There are other quiet people, but not like her. But is that bad, or do I really have to talk when I can't? I can't just desperately try to talk just for the sake of talking.

How do you see it?