Adaptation is a crucial part of history throughout civilization. Adaptation is also key to changing cultural opinions, fashions, and language. Even within generation of speakers and individual speakers undergo changes in language use, vocabulary, pronunciation, and syntax. The variation that is natural to language occurs because it is a complex system. If a language is living and in current use, then it is always adapting and emerging according to the properties of a complex system. Yet, when this stops happening for a language, and if it does not adapt then it becomes obsolete and is no longer an active complex system.