中古汉语有全清、次清、浊清三类声母,有平、上、去、入四个声调。但是在现代方言里,浊声母中的全浊,除少数方言外,都已清化,声调大都已分化为阴阳两类。古苗瑶语跟中古汉语一样,也有全清、次清、浊音三类声母,平、上、去、入四个声调。在现代苗瑶语的方言中,也跟现代汉语一样,绝大多数方言的浊声母已不同程度地清化,四个声调也都已分化或合并,唯独西家苗语还保持着完整的三母四声系统。 Middle Chinese has clear, clear, turbid clear three consonants, there are flat, on, go, into four tones. However, in modern dialects, voiced voices in all voices, except a few dialects, have been cleared, most of the tone has been divided into two types of yin and yang. Ancient Miao and Yao with Middle Chinese, there are clear, clear, voiced three consonants, flat, on, go, into the four tones. In the modern Miao-Yao dialect, as with modern Chinese, the voiced consonants of the vast majority of dialects have been cleared to varying degrees, and all four tones have also been divided or merged. Only Xijia Miao remained intact Three mother four sound system.