苗瑶语有左侧音节变调、右侧音节变调、左右侧音节变调、单音节变调,左侧音节变调、右侧音节变调与其名词短语句法结构的语序类型高度一致,左侧连读变调为右重韵律结构,右侧连读变调为左重韵律结构。
Tone sandhi occurs in Hmong-Mien langauges. The types of tone sandhi include the leftward tone sandhi, rightward tone sandhi, bidirectional tone sandhi (i.e. tone sandhi occurring both leftward and rightward), and monosyllabic tone sandhi. All types of tone sandhi have derivational and inflectional functions. The types of both leftward and rightward tone sandhi are highly harmonious with the word order of nominal compounds and the syntacic structures of nominal phrases. When it comes to prosodic structures, the leftward tone sandhi correlates with right-prominent prosodic structures, while the rightward tonal sandhi correlates with left-prominent prosodic structures.