从高本汉到王力,前人都把来母上古音值构拟为l,这是因为多处现代方言和中古以来的域外对音都对l;上世纪60年代后,经海内外学者三十来年的艰难探索才改定为r,并认识到r还能作二等和重纽三等的垫介音而形成cr复声母。这是借助汉藏语言比较、同源词古借词研究所得成果,光凭比较汉语方言,是无从得到这一结论的。但学界有推重“唯方言综合至上论”者,认为构拟要从方言综合、最小公倍数着手才是正途。孰不知若依此综合藏语方言,则必不能得到藏文的复声母,包括今读舌尖后音的cr,以及-s、-ld、-nd等尾等。实践出真知,既不能由此而复原藏文,足证此论之误。王辅世先生早年构拟的古苗语r、cr符合类型学,后来综合更多的苗语、瑶语方言,则把一些非词根的方言变化成分综合进重建的古音形式里去,反而不合了。这也同样可证从方言综合来构拟的想法是实行不通的,是要纠正的偏向。 From Gaobuhan to Wang Li, the predecessors have constructed the ancient Shangyin value as l, because many modern dialects and the foreign dialects since the Middle Ages are right. After the 1960s, scholars from home and abroad The difficult exploration was changed to r, and realized that r can also be used as second-class and third-class pads, etc., to form a sound pad cr complex. This is the result of comparison of Chinese and Tibetan languages, homonyms words borrowed ancient research results, just by comparing Chinese dialects, is impossible to get this conclusion. However, academics have to push their own emphasis on the “theory of the supremacy of the only dialect,” who believe that the proposed dialect synthesis, the least common multiple is the right way. If you do not know this comprehensive Tibetan dialect, you will not be able to get the compound vowels in Tibetan, including the tongue of today’s cr tongue, and -s, -ld, -nd and so on. If we practice our true knowledge, we can neither restore the Tibetan language nor prove that this theory is wrong. The ancient Miao language r and cr constructed by Wang Fu-shi in the early years conform to the typology. Later, when more comprehensive Miao and Yao dialects were integrated, some non-stemmed dialect variations were integrated into the rebuilt ancient form of sound instead. It is also true that the idea formulated from dialect synthesis is imposable and a bias to be corrected.