It's either staying silent because you're anxious and don't want to be rude by interrupting people. So you're just bored listening to a non stimulating conversation.

Or, the conversation is something you like a lot and you keep interrupting people and bothering them so the conversation ends.

The rare third option is you sync with another neuro atypical person and bounce back and forth with each other while everyone else stands their silent unable to follow a conversation that seems to make no sense. But makes perfect sense to you both.