Large language models such as GPT-5 and Llama systematically rate speakers of German dialects less favorably than those using Standard German. This is shown by a recent collaborative study between Johannes Gutenberg University Mainz (JGU) and the universities of Hamburg and Washington, in which Professor Katharina von der Wense and Minh Duc Bui played a leading role. The results, presented at this year’s Conference on Empirical Methods in Natural Language Processing (EMNLP) – one of the world’s leading conferences in computational linguistics – show that all tested AI systems reproduce social stereotypes.