The present volume reflects the proceedings of the fourth annual symposium at the Carnegie-Mellon University, which dealt with developmental linguistics in general and with child language acquisition in particular. Contents include an Introduction by John R. Hayes; "Derivational Complexity and Order of Acquisition in Child Speech," by R. Brown and C. Hanlon; "Comments on the Brown and Hanlon Paper," by W. C. Watt; "Discourse Agreement: How Children Answer Questions," by S. Ervin-Tripp; "An Experimental Approach to Children's Linguistic Competence," by C. S. Smith; "On Two Hypotheses Concerning Psycholinguistics," by W. C. Watts; "Experiments on the Segmentation of an Artifical Speech Analogue," J. R. Hayes and H. H. Clark; "On the Acquisition of Some Relational Terms," by M. Donaldson and R. J. Wales; "The Primitive Nature of Children's Relational Concepts," by H. H. Clark; and "The Cognitive Basis for Linguistic Structures," by T. G. Bever. A bibliography and author and subject indexes conclude the volume. (AMM)