The aims of our follow up observational study are to clarify the transition from prelinguistic communication to early language, and to show how dependent the development of verbal behaviour is upon the nature of the interaction which takes place between mother and child from the early months. Over a 22-month period, fortnightly, observations were made of 8 mothers and their firstborn children (2-23 months old) as they interacted at home, spontaneously and in semistructured situations. Maternal and child behaviours were recorded by timesampling method on the observation checklist consisting of 40 maternal and 65 child categories of behaviour. Data have been grouped into two-month age periods. In the present paper, we approached the topic of person and object in the development of communicative behaviour from two points of view: how “selfobject-person relation” was established and how it was used to further the dyadic interaction. Data was analyzed in terms of (a) frequency of child categories of behaviour: eye directions (FIG. 1, 2), arm and hand movements (FIG. 3), suckings (FIG. 4), vocalizations (FIG. 7) and frepuency of maternal categories of behaviour in play situations (FIG. 5, 6); (b) co-occurence of maternal or child categories of behaviour with each of the following child categories of behaviour: looking at mother, looking at object, looking at object held by self, touching mother, holding object and handling object (TABLE 3 to 8). It was demonstrated that “self-object-person relation” was established during 8-9 and 10-11 months of age; that is to say, interest of the child with physical objects and his acts of communication addressed to persons were combined systematically. In the previous 6 months, complex changes took place: at 2-3 months, reactions to persons were more frequent than reactions to objects, and these two reactions were not well differentiated, whereas at 4-5 and 6-7 months, reactions to persons and objects were differentiated with increased interest in exploring objects. During 12-13 to 18-19 months, the child showed improved “self-object-person relation” accompanied by intentional vocalizations. Finally, at 20-21 and 22-23 months, the child began to share their knowledge or intentions about objects with others by means of words. Moreover, the analysis of play situations revealed especially the role of mother in the development of child communicative behaviour described above.