How to explain linguistic variation and its role in language change

Linguistic variation is a feature that characterizes every natural language. In this paper, I focus on linguistic variation and its importance and its role in language change (LC). To determine its importance and role, one must distinguish between emergence and diffusion of variants because both dimensions provide different contributions to LC. The emergence and further development of new variants is a process that often (though not always) displays the form of a cycle, whereas the diffusion within a speech community often follows an S-curve form. Both dimensions are important for LC, but they relate to very different aspects. In this paper, I will treat variation with respect to its role in LC. Variation, in general, is a crucial factor in LC in two respects: First, it is the result of LC and second, it can trigger LC.