Unverständliche
Unverständliche is a German adjective that translates to "incomprehensible," "unintelligible," or "inscrutable" in English. It is used to describe something that cannot be understood, either due to its complexity, obscurity, or a lack of clarity. The term can apply to a wide range of subjects, from spoken or written language to abstract concepts or even the motivations of individuals.
When referring to language, unintelligible might describe speech that is too fast, mumbled, or uses a dialect