According to the World Atlas of Language Structure there are nearly seven thousand languages spoken throughout the world and more than half of the worlds' population is estimated to be bilingual and engages in code switching. Due to such statistics it becomes obvious that nowadays the alternation between two languages is rather the norm than exception in many communities. However, the fact that bilingualism is so widespread is not the only reason why there has been and still is such an interest in this phenomenon as a research topic. The question arises why the study of language behaviour over and over remains an interesting subject in linguistic research.