Too often in stories, people can say as much as they want with no consequences. Time seems to stand still while characters are speaking. The day doesn't progress; characters do not get winded, hungry, thirsty, or otherwise distracted; even falling objects seem to wait while characters speak their minds.
The idea that talking is a free action borrows heavily from the rules in Dungeons & Dragons. And in certain aspects, it can be a wonderful thing. It's fine for games that are meant to be enjoyed, bu ignoring it takes away from reality (if that's what you are trying to build).
Speaking takes time. It takes effort. It takes mental energy to form thoughts and physical energy to communicate them. They are generally minute quantities, but they can add up. They can also be enough to throw somebody off their conversation.
Try playing around with the timing of talking. Look to real life to see how it can affect people positively or negatively, and experiment with how that can be used dramatically in your stories.