A contributor in a conversation; someone who plays a role in a discussion or debate
A go-between or messenger who relays information between parties
Even if you don't recognize the word interlocutor, you probably rely heavily on at least one. When stressful thoughts bubble up and threaten to overflow, you turn to an interlocutor to vent and get advice. And when you're struggling with a confusing problem or ethical dilemma, talking to an interlocutor can get your thoughts in order and help you to consider new perspectives. Parents, friends, therapists, attentive baristas - all are interlocutors we count on being able to turn to when we just need to talk. When you want to say: “the person who was talking to me”, you can simply say: “my interlocutor”.
Although it's great to be able to talk to an interlocutor you know on a personal level, the word doesn't only apply to those with whom you discuss your deepest problems. In general, an interlocutor is just someone who's talking to others and playing a contributing role in a conversation. That may sound like a simplistic definition, but it comes with some important specifications. First, an interlocutor has to talk, at least a little - someone who chooses to pensively sip tea while the people on either side converse wouldn't fit the bill. Furthermore, to be an interlocutor requires participation in a discussion; the exchange of ideas has to be going two ways. Lecturing teachers, keynote speakers, and people yelling through megaphones on soapboxes all may be eager to voice their opinions, but the word doesn't apply to them because they're not expecting responses (beyond things like clapping and spitballs).
But as long as those two very broad conditions are met, interlocutor can be used in a number of situations. Any type of conversation, no matter how casual, necessarily involves interlocutors, but the word is especially useful for describing those who participate in scholarly or philosophical dialogues. In these cases, the use of interlocutor implies a discusser who is trying to settle an intellectual debate or stimulate consideration of a topic; think of Socrates posing questions to his fellow Athenians, or of Abbott and Costello working out who was on first.
The word is also frequently used to describe someone who carries messages between parties that otherwise wouldn't communicate. Many governments are said to use interlocutors to explain policies, stimulate discussion among the people they serve, and bring back information. Interlocutors in this sense are similar to mediators, who also start conversations and relay information. A mediator, however, usually has the specific role of helping opposing parties come to agreements or find common ground. By definition, an interlocutor can fill this role as well, but if it’s not specifically stated, there's no reason to assume this is the case. Mediators are also expected to be neutral individuals who aren't connected to either side, while interlocutors may or may not be biased or free to express their opinions. You'd be right to say that all mediators are interlocutors, but not all interlocutors are mediators.
One final, outdated use of interlocutor that you might still stumble upon references a stock character in the American minstrel shows of the 19th century. In these shows, the interlocutor, situated between two comics, served as a straight-man. His role was to ask leading questions and start discussions between the two comics, who would answer clownishly for the entertainment of the audience. The interlocutor was often a parody of an upper-class American gentleman, and his affected manners and vocabulary would be ridiculed by the two comics. Although the minstrel show has long since faded away (thankfully, as they were usually racist), the implication of an interlocutor as a middleman remains in some of its usages today.
Example: The interlocutors enjoyed a lovely conversation about the outdoors during a walk in the park.
Example: He enjoyed bantering with friendly interlocutors on Twitter.
Example: As a teenager, I loved being an interlocutor on my school's debate team.
Example: With her sisters refusing to talk to each other, Alice was forced to serve as an interlocutor, explaining to each how the other was feeling.
Example: The philosophy professor was renowned among academic circles as a great interlocutor.
In many situations where interlocutor is used, it's implied that the speakers are involved in a respectful, rational discussion of something important. They're students of logic, or perhaps a couple of friendly idealists enthusiastically yet politely debating a point about ethics. But although that's how the word is understood today, interlocutor's origins may refer to communicators who weren’t quite so courteous. Interlocutor's earliest ancestor is thought to be the Latin interloqui. Formed from the roots inter- (meaning "between, in the middle of," as in intersection or interrupt) and loqui ("to talk," as in loquacious or elocution), interloqui literally means "to talk in the middle of" or "to interrupt." So, while interlocutor today often refers to people who are talking while literally situated between others, its forerunner might conjure images of overexcited Romans shouting over each other. "Now, I'ma let you finish, Caesar…."
Interlocutory: This somewhat uncommon adjective can describe something as related to or containing discussion. Interlocutory is also a useful legal term, referring to a “provisional or temporary decision” or to any other relevant event that happens while a trial is underway.
Example: Their interlocutory relationship was founded on long conversations over coffees and chess games.
Example: An interlocutory hearing was needed to decide if the witness should be held in contempt of court.
Interlocution: (noun) Interlocution refers to the act of conversation. It's an academic word, and it might work best when describing very academic conversations.
Example: The interlocution with my classmate about the theories of Immanuel Kant left me more confused than before.
In general, there's nothing wrong with being or talking to an interlocutor; who doesn't like a nice conversation? But if you're tired out, and all you want is some "me" time, you might not welcome an interlocutor trying to get you to talk. An interlocutor or anyone else who you don't want around would be an interloper, a noun which describes someone who's intruding or shouldn't be present. On the other hand, an interlocuter who asks you a series of detailed, intense, and possibly aggressive questions could be more specifically called an interrogator. Take care not to confuse these three similar sounding words, since they would all say something different about the person you're describing.
From Charlotte Brontë's Jane Eyre:
"As to the mouth, it delights at times in laughter; it is disposed to impart all that the brain conceives; though I daresay it would be silent on much the heart experiences. Mobile and flexible, it was never intended to be compressed in the eternal silence of solitude: it is a mouth which should speak much and smile often, and have human affection for its interlocutor."
This passage is part of the character Mr. Rochester's description of Jane Eyre. Rochester, who is, strangely, disguised as an old gypsy woman, describes Eyre's mouth as full of character and ready to impart intelligent thoughts to a person in conversation, or an interlocutor.
An interlocutor is involved in dialog
You can't have a conversation if you interrupt your interlocutor
Interlocutor: Inter + Loquacious
Bring out the linguist in you! What is your own interpretation of interlocutor. Did you use interlocutor in a game? Provide an example sentence or a literary quote.