I have a habit of speaking too briefly and expecting whomever it is that is listening to fill in the missing words. When I listen carefully to other people’s speech patterns it becomes obvious that many people truncate their sentences too. Often this happens when the interlocutor understands what is about to be said, so they mentally complete the sentence, and begin talking themselves. Another accepted form of truncated speech is when people say things like, “Yes,” “No,” “Thank you,” and other such things as if they were complete thoughts. Perhaps by some definitions they are complete sentences, and normally in conversation they are accepted as appropriate statements. My concern is that when these statements are made they are not making a complete enough linkage to the events to which they are supposedly connected.
“Yes, I want some more potatoes.” “No, I don’t want any more beets.” “Thank you, for the potatoes.” Each of those sentences is more informative than the briefer, “Yes,” “No,” and “Thank you.” Unless the context is well understood by both parties, those statements are meaningless. I am quick to agree that those more complete sentences sound stilted, but they carry a more complete meaning, and everyone concerned knows what is being intended by the words.