This certainly can be one way to look at it. As a workshop presenter, I schedule talking pauses after important concepts are introduced. This allows the participants, whether they be students or teachers, to discuss their thoughts on the topic with a neighbor or with the other people at their table. Write down any new thoughts and ideas you generate so that you won't forget them later. Then I give everyone several minutes to talk while I walk around listening and monitoring the individual discussions.
Students are bored.
As teachers, this can result in grading papers, planning units or lessons, or filling out paperwork during in-services or meetings. Our students don't have nearly the responsibilities that we do, so they naturally turn to talking about subjects that do interest them. Keep student interest is an important way to curb talking. If your students are conversing during a lesson, take a moment to consider why. If your students are bored, you need to stop what you are doing and surprise them.