The Monopolizing Loudmouth seems to have a rebuttal for every comment made and becomes loudest when someone contradicts them or if the chair does not allow them to defend their "honor". They control the meetings with intimidation, volume, and egocentricity.
Solution: The chair must be brave enough to stop the barrage of words from the Monopolizing Loudmouth by recognizing only any member who has not yet spoken, and by defending the new speaker's right to be recognized. Here are a few effective controlling statements:
"Please direct your comments to the chair and not to another member"
"Did you wish to rescind the motion, (or give notice to rescind, or move to reconsider a vote)?"
"Excuse me, but according to our rules, you have exhausted your debate times and debate length"
"We have a speaking queue, and you need to wait your turn on the queue"
The best way to a handle the Monopolizing Loudmouth is adhering to proper debate protocol. Making sure all members have an opportunity to speak and prioritizing speakers that have not yet spoken will help empower other members to be included. Enforcing the standard debate limit of only allowing members to speak twice in debate (for a maximum of 10 minutes per time) will further limit the monopolizing effect of these kind of members. Ten minutes is a long time to allow a single member to speak and is the default in Robert's Rules so that it is sufficient for all types of meetings and organizations. However, if this becomes an issue, it is highly advisable to pass a Special Rule of Order to set debate limits to a shorter duration, often 2-3 minutes.
If the Monopolizing Loudmouth attempts to pontificate outside of debate, they can be reminded that there is not an active motion on the floor and that a motion is required to conduct business. This will prevent the a common time-waster in meetings of members talking at length about perceived problems without offering any solutions.
If this member is becoming belligerent to other members, reminding them to direct their comments to the chair can allow you to serve as a buffer and prevent disagreements from becoming personal or getting out of control.
In extreme circumstances, it may be advisable to call the member by name, call a recess to allow emotions to cool and speak privately with the member, or remove the member from the meeting. Keep in mind that, while a chair may remove non-members unilaterally, the chair does not have authority to remove a member from a meeting and such an action requires a 2/3 vote to accomplish. This ensures due process for members and prevents a chair from removing members unfairly.
Above all, remain patient and firm with all misbehaving members. Try to kindly explain why their actions are inappropriate, seek to understand their intentions, and offer advice on how they can properly achieve their goals. Often a little guidance can go a long way to creating a more equitable and inclusive environment.