Teeth are black. Yiwu dialect, a dialect of Wu dialect, belongs to the golden qu film of Wu dialect, which is mainly used in Yiwu city, Zhejiang province, and is represented by Yiwu dialect. In Yiwu dialect, moldy teeth mean that the root of dental mold is black. Due to the convenient land and water transportation and frequent communication with the outside world, Yiwu dialect is greatly influenced by surrounding dialects, resulting in many differences within Yiwu dialect. There is a saying that there are eighteen dialects in Yiwu, but it is different across a stream.