The Sino-Tibetan stock outlined above has been set up on the basis of a series of monosyllabic roots shared by Tibeto-Karen and Chinese. As shown below, certain phonetic generalizations regarding these roots can be laid down, and we have no reason to distrust the genetic implications of this material. Both branches of Sino-Tibetan are characterized by the use of monosyllabic roots and the development of tonal systems, yet neither of these features is of ‘critical’ value, since each is shared by other stocks (Thai, Miao-Yao). As for syntax, Chinese and Karen place the object after the verb, while all Tibeto-Burman languages, without exception, place the object before the verb. In view of the generally archaic nature of Tibeto-Burman morphology, it is suggested that the Tibeto-Burman arrangement is the original one, whereas the Chinese and Karen word-order has been influenced by that of contiguous stocks (Thai, Miao-Yao, Mon-Khmer), all of verb + object type. The agreement in syntax between Karen and Chinese thus appears to be of secondary origin, and in any event is quite overshadowed by the preponderant lexical agreement between Karen and Tibeto-Burman. In general, lexical considerations are here of primary importance, morphological and syntactical considerations of secondary importance.