Which motion may not interrupt a speaker and is also not open to debate?

The motion that may not interrupt a speaker and is also not open to debate is a motion to call for a recess. This type of motion is used to take a break during a meeting without disrupting the flow of the discussion. A recess does not allow for interruption of a speaker currently addressing the assembly because maintaining order is essential in parliamentary procedure. Additionally, since it is a motion to temporarily suspend business rather than a point of discussion, it does not involve debate among the members.

Other motions like a question of privilege and a point of order can interrupt a speaker, as they relate directly to the needs of the assembly or the proper conduct of the meeting. Parliamentary inquiry is similarly a request for clarification that can interrupt but is meant to gather information rather than take a vote or change the status of the meeting directly. Thus, recognizing the specific roles and limitations of each type of motion is key to understanding why the motion to recess fits the criteria described in the question.