The article gives a review about perceptional processes of proper names and its results after decades of exploration in the field of Sorbian-German contacts in everyday speech in the Middle ages. The toponymic material belongs to the region between the rivers Saale and Elbe in the West and the rivers Queis, Bober, Oder in the East of the considered regions. Phenomena recognized of systematical evidence are described in detail, i. e. phonematical, graphematical, morphematical, lexical, and semantical facts are performed. Phases of onymic integration, transsumption and transposition are exemplified. The process of integration is illustrated by variants of onyms as well as by processes of adaptation. Special attention is mentioned to the borrowing events of German place names in Sorbian language since the Middle ages.