Abstract
While linguistic representations are unlimited, some fundamental structural relations are local : they must be satisfied within a very limited portion of structure. For example, grammatical agreement phenomena must typically be satisfied locally; they cannot be established at a distance. Yet some phenomena appear to be able to cover unlimited structural distances : for example, in a question, the interrogative element can be found at a potentially unlimited distance from the verb with which it is to be related (Who and the verb meet in the sentence Who do you think we were told that people think...that we'll have to meet __?) But detailed comparative analysis shows that these apparently unlimited displacement phenomena are to be broken down into a series of steps, each of which satisfies constraining principles of locality. The study of the nature and properties of these principles is one of the important themes of formal language research.
