The incomprehensible vocalizing and babbling of infants and the final emergence of true language from this prolonged period of practice have attracted the attention of writers in many fields, and particularly those in the field of child study. The bulk of the literature on this topic consists of a large group of semi-scientific observational studies of a biographical nature, which appeared during the last decades of the nineteenth century and the first part of the present century. Many of these records are concerned, not only with language development but also with motor, social, and emotional development. Other studies, however, are much more defined in purpose, and are somewhat narrower in scope, being confined to the study of the child's acquisition of language. The studies which give adequate reports of the very early stages, however, are much less numerous than those which are concerned chiefly with the period immediately following the appearance of the first word. Unfortunately, the studies which involve the observation of many children under controlled conditions are very few in number and much needs to be done along this line.Previous Reviews: The literature on this topic has been brought together from time to time by various writers. Most of the available reviews, however, are concerned chiefly with the vocabulary studies 625 626 DOROTHEA McCARTHY on older children, and little or no space is devoted to the earliest stages of linguistic babbling. They consist chiefly of tabulations of all reports on the appearance of the first word, or of tabular comparisons of different vocabulary counts. In 1833 Feldman (15) gave such a review based on the records of 33 children. The mode of this group for the appearance of the first word was at sixteen months. In 1883 a very brief review of foreign studies was given by Sikorski (55). Preyer (48) in reporting his son's progress in language compares it with the earlier reports in the literature, particularly those of Stumpf (62), Lindner (32 and 33), Sigismund (54), and others. In 1891 Sanford (50) gave a very brief and incomplete summary of what had been done in the field up to that time. Tracy (67) in 1893 gave a vei-y clear and complete summary' of the studies of children's language up to two years of age. He calls it " an outline history of the speech-progress of the average child during the first two years, generalizing from a large number of observations made by different persons on different children." While it is difficult to combine the records from these biographical studies because of the different methods of observation, Tracy (67) has made the most satisfactory summary of the literature on these early stages. Neumann (39) gives an excellent discussion of the early anecdotal accounts in the foreign literature, particularly those of Ament (2), Lindner (32 and 33), Gheorgor (20), and others. In 1907 Clara and William Stern in their book called Children's Speech (58), gave an excellent account of all the observations on German children as well as on children of ...