I read on another topic that "han yu" was fhe collective name for the languages of China (and would include traditional Chinese and Cantonese) and "zhong wen" specifically referred to Mandarin Chinese. Not sure if this is true.
Should there be equivalent expressions taught for the other languages taught on Duo? For instance, in the course teaching Hindi, it would say, "They do not speak English. We do not speak Hindi. What do we do?"