China has always been a large country wherein people spoke a number of varying dialects of the Chinese language. These dialects were sometimes so different as to make the speaker of one dialect completely incomprehensible to the speaker of another, although both parties were technically speaking Chinese. In pre-modern times, there was no national language like Mandarin that was applicable throughout China.
In wuxia fiction, characters often travel all around the country. No matter where they go, however, the characters seem to be able to communicate easily with the locals. What happened to the language barrier? What language was everybody supposedly speaking?