From the Harvard Business Review:

There are three stages of speaking to other people. In the first stage, you’re on task, relevant and concise. But then you unconsciously discover that the more you talk, the more you feel relief. Ahh, so wonderful and tension-relieving for you… but not so much fun for the receiver. This is the second stage – when it feels so good to talk, you don’t even notice the other person is not listening. The third stage occurs after you have lost track of what you were saying and begin to realize you might need to reel the other person back in. If during the third stage of this monologue poorly disguised as a conversation you unconsciously sense that the other person is getting a bit fidgety, guess what happens then? Unfortunately, rather than finding a way to reengage your innocent victim through having them talk and then listening to them, instead the usual impulse is to talk even more in an effort to regain their interest.

I struggle with this and, over the years, have developed a semi-conscious habit of putting my hand over my mouth when having a conversation as a reminder to listen instead of talk. The author suggests a couple of reasons some of us talk too much:

The process of talking about ourselves releases dopamine, the pleasure hormone. One of the reasons gabby people keep gabbing is because they become addicted to that pleasure. [and] Some people are long-winded is because they’re trying to impress their conversational counterpart with how smart they are, often because they don’t actually feel that way underneath.

Way back in 2010 I had an idea for an app I called the Blab-O-Meter. You turn on Blab-o-meter and it begins monitoring how much you are talking. You can set the app to alert you by vibrating and or playing a sound (a throat clearing; “shhhhh!” etc) when you exceed some predetermined level. 50 percent might be reasonable or, if you’re trying to listen more, set it lower.