Convergence and Divergence of Dialects: Language Change or Cognitive Dialectology?

In this paper two approaches to the concepts of convergence and divergence are described. The first concerns dialects as linguistic systems that may converge or diverge from each other or from the standard language, the second level concerns convergence and divergence as linguistic behaviour of in relation to the various registers a bilectal speaker has at his or her disposal. It is claimed that the latter approach is the more fruitful one in socio-dialectological research.