This volume brings together a collection of papers centred on the theme of the psychological functions that are built up by communication in the developing child. It is part of a series that aims to integrate social and cognitive development research on the developing child within his/her environment. The approach strives to overcome impasses that are outgrowths of two traditional themes in psychology. First is the fundamental general biological issue of the contributions of the organism and its environment to the development of the former. The second is how we can understand social development in human ontogeny, and in which ways (if any) human social development differs from that of other species.