It can be challenging to find the time to suggest to an employee that they either speak up or speak less. This individual approach can lead to resentment and further encourage behaviour that lies at opposite ends of the scale. A key thing to realize is that it would be uninspiring to lead a team where everyone was the same.
Some might interpret your silence in the face of the steady flow of conversation as indifference or disapproval because the conversation does not meet your intellectual standards. In fact, you may be very interested in all that's being said. You just don't have the confidence or energy to jump into the conversational fray.
It's sometimes easy to feel that our world favours those who are more extroverted, that we need to be outgoing and gregarious to succeed in the workplace and in our social lives. You see, I've always categorized myself as an introvert, which may seem at odds with my industry -- after all PR is about being "out there" a whole lot.