A Brief History of Modern Linguistics

As de Saussure regarded language as form and not substance (as basically everyone after him), he was naturally more interested in langue and how, at one point in time, a language was constructed so that human communication was possible. But if we can not conceive of language as representing essential elements, but rather as arbitrary concepts and sound-images, who only gain their identity by virtue of their position (and, hence, difference) to other units in the same system, how can we account for linguistic change? Since we need a rather rigid system to be able to communicate without interruption, the system needs a reasonable amount of fixity. But if the elements of a system all stand in a differential relation to others, how do new meanings emerge? It is obvious that some meanings change or that the same signifier can stand for multiple signifieds. Sometimes even completely new signs have to be found and in which relation do we place them?