In my article ‘On the tone system of the Miao-Yao languages‘ I dealt chiefly with Miao data. With the additional data on Yao made available in recent publications I can now reconstruct the tonal system of Proto-Yao in greater detail and with more certainty.
The terms Miao and Yao refer both to peoples and to languages. The Yao people speak Mien, a Yao language; Punu, a Miao language; and Laka, a language whose relations are still uncertain. Yao, in contrast to Miao, has a complicated system of finals: vowels may occur in final position, or they may be followed by -y, -w, -p, -m, -t, -n, -k (in some dialects _?), or -η). Miao, on the other hand, has a complicated system of initials, with both simple consonants and consonant clusters, which Yao for the most part lacks. Some differences in vocabulary also characterize the two.