Kenneth G. Wilson (1923–). The Columbia Guide to Standard American English. 1993.
SITUATION UTTERANCE, RESPONSE UTTERANCE
C. C. Fries (1952) used these terms to describe the two clusters of syntax he encountered in American English speech. Essentially, situation utterances begin conversations, and response utterances continue or end them. A situation utterance normally requires a complete sentence, a question, statement, or command: Is Fred home? I have your book. Call me on Thursday. A response utterance, however, can be any sort of syntactic fragment, based as it is on the situation utterance that elicited it: Not yet. Good. If you wish. Of course. Never. Why not? Both kinds of syntax are Standard in speech. In expository writing, nearly all sentences are situation types; because you cannot see your readers, you cannot risk losing them by using a fragmentary response sentence, unless you carefully control it with context. And much of the time such fragments will sound too informal for Formal or Semiformal writing. In writing dialogue, you will of course use both kinds of utterances, but otherwise when writing, reserve the fragmentary response utterance for very special circumstances.
