One reported German expression for something incomprehensible: “Mesopotamisch”. Another one: “Kauderwelsch” (possibly referring to the Rhaeto-Romance language spoken in Switzerland)

“Das ist mir Böhmischer Dörfer” (’That’s Bohemian villages to me”) - this German reference to the incomprehension (or at least impronouncability) of Bohemian (i.e. Czech) village names is mirrored in the Slovak expression “Je pre mňa španielska dedina” (”(That) is for me a Spanish village”), and in the Slovenian one “To mi je španska vas” (”This is a Spanish village to me”) . Other related expressions, not just dealing with incomprehension so much as just plain chaos, are “Czeski film” (”Czech movie”) in Polish, for a kafkaesque situation, for example in dealing with bureaucracy. German has “polnische Wirtschaft” (”Polish economy”) for a chaotic situation and “Fachchinesisch” for technical jargon.