The Czech Republic borders on Germany, and even though the number of German speakers in Czechia has been declining, about 20% of Czechs still speak some German. In Kafka's time many places in Czechia still had Czech as well as German names.
On top of that his parents spoke primarily German.
Here's what Wikipedia has to say about his upringing:
> His family were German-speaking middle-class Ashkenazi Jews. [...] Kafka's parents probably spoke a German influenced by Yiddish that was sometimes pejoratively called Mauscheldeutsch, but, as the German language was considered the vehicle of social mobility, they probably encouraged their children to speak Standard German.
Also all the schools he attended taught in German. That is elementary school, Gymnasium (secondary school), and the university he attended.
It's really not comparable to authors writing in a language that is not "native" to them.
On top of that his parents spoke primarily German.
Here's what Wikipedia has to say about his upringing:
> His family were German-speaking middle-class Ashkenazi Jews. [...] Kafka's parents probably spoke a German influenced by Yiddish that was sometimes pejoratively called Mauscheldeutsch, but, as the German language was considered the vehicle of social mobility, they probably encouraged their children to speak Standard German.
Also all the schools he attended taught in German. That is elementary school, Gymnasium (secondary school), and the university he attended.
It's really not comparable to authors writing in a language that is not "native" to them.
https://en.wikipedia.org/wiki/Franz_Kafka#Life