The present paper is concerning with Franz Kafka's German. It calls in question the theories about the poor, impoverished and insular character of Kafka's Prague (ghetto) German in isolation from a German speaking community. The paper presents Franz Kafka's in its temporal, regional and social context: (1) His German participates in the contemporary development of the German language. (2) The German of his private letters and diaries is a variety with several spoken and Bavarian characteristic features in the phonology, morphology, syntax and lexicon, but the German of his official letters and manucripts contains largely only lexical, especially terminological law Austriacisms. So Franz Kafka had a good command of all language registers. (3) Some phenomena in Franz Kafka's German have parallels in Czech and Yiddish. Some of these phenomena are to interpret as Baiuvarisms too, some other as collective phenomena in the German speaking in Bohemia.