Final answer:
In the U.S. Senate, a member can speak indefinitely on a debatable motion on the same day unless a cloture motion is passed to limit or end the debate.
Step-by-step explanation:
In the United States Senate, there is a tradition of unlimited debate on legislation, which is significantly different from other legislative bodies where there may be strict time limits. Each senator can debate as long as they wish on a debatable motion, assuming no formal time limits have been agreed upon by the Senate. The debate only concludes when there is a motion to table that is voted upon or no senators seek further recognition to speak. This tradition is often associated with the practice known as a filibuster, where senators continue to debate an issue to delay or prevent a vote. A cloture motion, requiring a supermajority of 60 votes, is needed to end the debate. Therefore, a member can essentially make speeches indefinitely on the same motion on the same day unless a cloture motion passes.