interlocutor

noun

1. A person who takes part in dialogue or conversation: a locutive partner.

   “Explanations which continually remind one's interlocutor of one's ignorance are a great damper upon the easy flow of talk.”

   “In the run-up to his return to the White House next Monday, Mr. Trump has rattled the world, and America’s neighborhood in particular, with a list of objectives – buying Greenland, seizing the Panama Canal, making Canada the 51st state – that treat friendly nations as weak interlocutors and impediments to be subdued.”

2. A man in the middle of the line in a minstrel show who questions the endmen and acts as leader.

   “The "interlocutor" greeted the audience and engaged in comical repartee with the "end men," named Tambo and Bones.”

3. An interlocutory judgement or sentence.
4. A decree of a court.

   “A decree of the English Court of Chancery is not entitled to more respect in Scotland than a decree (interlocutor) of the Scottish Court of Session in England.”