In this article I discuss linguistic relations in Upper Silesia. In due course of historical processes there are three main language codes in use in Upper Silesia: general Polish, Silesian dialect, Borderlands dialect. Their usage is dependent of many factors. The most important are: local group affiliation, age, education, place of living. The most common code in Upper Silesia is general Polish. It is used by representatives of all local groups. Silesian dialect is used by Silesians, mostly in unofficial situations. Borderlands dialect and German have smaller domain. Borderlands dialect is a domestic language for people who came to the Silesia from the South-Eastern Borderlands of the II Polish Republic and German is used during the official meetings of the members of German minority.