Taking turns

At times, certain players tend to monopolize the group's playing time. Sometimes it's due to overconfidence or deliberation, but the opposite--diffidence, confusion--can also tend to slow the game down. One way to solve this problem is to roll for metagame initiative. What I might do is have the players roll for what order they take turns in, and then every time a point of confusion comes up, all of us (the GM included) might roll to determine who speaks first to offer suggestions to resolve the situation. The goal here is to keep the game moving.