Teacher Commentary
While the partners are talking, move through the room and listen in to the conversations. Notice conversations that feature a common roadblock, a particularly interesting question or connection, or an “ah-ha!” moment when meaning was made. Ask individuals if they will be willing to share out what they have been discussing when you switch to the whole group. Encourage the speakers to recount their whole process of problem solving or meaning making.

Alternatively, you can use a lottery system based on drawing names randomly. Let students know before they begin discussing in partners that you will call on some students to share with the whole class. Again, encourage students to make their thinking visible whether or not they reached an understanding. Surfacing unanswered questions allows the whole room to contribute to the construction of knowledge.
I use a combination of both strategies, depending on the situation. What I strive to avoid is a discussion where there are a few constant voices whose contributions focus on answers but not thinking processes. I consider the class a success if all students get multiple chances to speak and be heard, both in small groups and in front of the class. The more frequent the opportunities, the lower the pressure and anxiety.