A COURSE ON LINGUISTICS usually follows one of the general models, or theories, of natural language, as well as the corresponding methods of interpretation of the linguistic phenomena.
A comparison with physics is appropriate here once more. For a long time, the Newtonian theory had excluded all other methods of interpretation of phenomena in mechanics. Later, Einstein’s theory of relativity incorporated the Newtonian theory as an extreme case, and in its turn for a long time excluded other methods of interpretation of a rather vast class of phenomena. Such exclusivity can be explained by the great power of purely mathematical description of natural phenomena in physics, where theories describe well-known facts and predict with good accuracy the other facts that have not yet been observed.
In general linguistics, the phenomena under investigation are much more complicated and variable from one object (i.e., language) to another than in physics. Therefore, the criteria for accuracy of description and prediction of new facts are not so clear-cut in this field, allowing different approaches to coexist, affect each other, compete, or merge. Because of this, linguistics has a rich history with many different approaches that formed the basis for the current linguistic theories.
Let us give now a short retrospective of the development of general linguistics in the twentieth century. The reader should not be worried if he or she does not know many terms in this review not yet introduced in this book. There will be another place for strict definitions in this book.