In other words: should it be “Guess what?” or “Guess what!”? Or does the correct usage depend on the context and intent of the speaker?
If "Guess what" is to be a complete sentence, it's unequivocally an imperative one. Logically, if not linguistically, the reply has to be a question itself…
…unless the responder actually plans to guess.
I think it can vary by speaker. My inclination would be to use "guess what?" when the speaker pauses to accept guesses, and "guess what!" when the speaker keeps on speaking, thus:
"I got something for you," Sue said brightly. "Guess what?"
"A book? ... a donut? ... a chicken?" Fred guessed.
"No, silly! The keys you left at the restaurant!"
"Guess what!" Sally shouted as she ran into the room. "I made bail!"
Logically it seems that it is an imperative statement. But if you do a google search for "guess what" or a COCA search for "guess what" you'll see that it is quite frequently written as a question. In addition to the two cases mentioned by Hellion it is also used in other ways, such as
In these examples it's neither an imperative nor a question.
I know this question was posted a long time ago, but I feel the need to chime in.
In regards to Hellion's response: "Guess what" would never be punctuated with a question mark. My reason for saying that is because of the inflection. Listen to how statements and questions are said. A statement (such as "I am so happy.") starts high in tone and ends lower in tone. A question (such as "How are you doing?") starts lower and ends higher. Inflection always dictates how a sentence is punctuated. When someone says "Guess what", it never sounds like a question. It is a command; you are telling someone to do something.
Say a couple of short questions out loud, listen to the inflection, then say "Guess what" last and you will see what I'm talking about.
I think a lot of people punctuate this sentence incorrectly for two reasons:
- The word guess implies that thought is required for the response.
- The word what is commonly used in questions (who, what, where, why, and how).
A good example as to why I think this is the case lies in another sentence that gets punctuated incorrectly: "I wonder what he is thinking." A lot of people would punctuate this with a question mark because "wonder" implies thought and the word "what" is being used. But, this is a statement. You are saying that you're doing something (wondering), not asking a question. Similarly, listen to the inflection in this sentence. It starts high and ends low—the opposite of how a question sounds.
Actually, "guess what" can be written correctly as a question. For example, the following dialogue:
Eric is having conversation with Ashley. Ashley: "Hey! I just got my test score back!" Eric: "Oh, yeah, how'd you do?" Ashley: "Try to guess" Paul overhears conversation at this point and joins in "Guess what?" (as in "[I didn't hear the conversation before. Try to] guess what?)
Other than this type of situation, I believe it's punctuated with a period or an exclamation point.
Copywriters, there's a simple answer to this question. If it is intended as a question, it requires a question sign. If it is intended as an excited statement, an exclamation sign is in order.
Think about it. What is a question? It is a sentence which anticipates and expects an answer. Therefore if you ask "Guess who is coming to dinner?" and expect an answer, it is a question.