In my article 'On the tone system of the Miao-Yao languages'l 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.2 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 -9. 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. The Yao dialects whose tone systems I shall discuss here are the following. 1. HKP: Herbert Purnell Jr. studied the dialect of Hweikang Pa (Yanglae), in the District of Maechan, Chiengrai Province, North Thailand, from April 1963 to May 1964. His Phonology of a Yao dialect contains perhaps three hundred forms. The tones of HKP are (1) mid-high (unmarked): normally level, an occasional alternant has a very slight fall: mhyen 'face';4 (2) mid: a falling contour beginning around the middle of the vocal range and ending near the bottom: my6n 'people'; (3) high: a slight rise followed by a fall to median pitch when the syllable does not end in a stop: cui 'dog'; level when the syllable ends in a stop: sip 'red'; (4) low-mid: slightly rising followed by a fall to the bottom of the range, with pharyngealization throughout: tui 'pig'; (5) mid-low: a rising contour beginning slightly below median pitch and ending somewhat above it: pw6y 'to sleep'; (6) low: level, with glottalization ('creakiness') throughout, occasionally with a very slight fall: nin 'to eat', tUb 'bean'. 2. PKT: In 1959 and 1960, G. B. Downer collected data from the villages of P'u K'amteng and Chungliang, about four and seven hours respectively from Muongluang Namtha on the Muongsai trail in northwestern Laos. His 'Phonology of the word in Highland Yao'6 contains more than two hundred examples and a short text. The tones of PKT are (1) mid-high level: hman 'face'; (2) midhigh, falling to low: mian 'people'; (3) high rising-falling: only when the syllable