The author gives a brief review of the facts concerning differences between the forms of speech used by the two sexes in certain primitive peoples, and then proceeds to a consideration of the chief theories hitherto advanced to account for these differences. The theories are classed as historical (that the women's speech represents a remnant of the speech of a conquered race), social-economic (that the speech differences are due to sex differences in occupation), psychological (that the differences are analogous to the spontaneous efforts at speech-construction made by young children) and religious (that the differences can be traced to taboos on certain words). Most of these theories (except perhaps the first) have, it is