In this paper, the behaviours of adverbs which are used like the German (separable) verb prefixes are investigated, using texts collected by the author from young Upper Sorbs. The adverbs attested are not only Upper Sorbian words, but also German ones like hin “to (a direction)” or los “(set/ go/ fly/ run/ ...) off”. According to frequency, such Upper Sorbian adverbs predominantly appear immediately before the verbs to which they attach. If we focus on the semantic construction of the cases in question, it plays an important role in what the speaker sees as one act. From a wider perspective, these adverbs might go the way of grammaticalization. Perhaps we are seeing the birth of new grammar. As this phenomenon might also be an ongoing language change process, however, we must still observe it carefully.