Wikipedia has an interesting (for me, at least) definition of question: "A question is a linguistic expression used to make a request for information, or the request made using such an expression." This means that there are two senses of the word "question": one very general and abstract (a question is an abstract sequence of words, even it no one asks it), the other one concrete (a question is a concrete asking for information). In the abstract sense, all persons who have ever asked, say, what's the capital of Portugal, they were asking the same question. But here is my problem: in this abstract sense (or perhaps in another possible abstract sense), a question is not a linguistic expression (although Wikipedia says so...), since the same question can be formulated in any language or in different ways within the same language: many linguistic expressions can formulate the same question. A question is an abstraction, something like a thought (that many people can think). What is special about (abstract) questions is that they are not "declarative thoughts", but "interrogative thoughts". Could you tell me more exactly what kind of abstraction (abstract) questions are? (By the way, does it work for orders and requests too?)