This paper describes an assessment instrument being developed to trace the emergence of social-communication skills leading to language and the neo-Piagetian model that is directing the assessment construction efforts. The model is a structural stage model, based on the writings and research of Uzgiris (1976), McCall, Eichorn & Hogarty (1977), and Fischer (1977). The model analyzes social-communication into distinct developmental dimensions focused on different social-communicative problems confronting the infant, each of which forms the basis for an individual scale of the assessment instrument. This set of social-communication scales and a set of object scales (adapted from Uzgiris & Hunt, 1975) have been organized according to developmental levels that the model asserts should reflect common underlying structural organization across both domains. Results of research with a group of handicapped infants and toddlers, which examined the pattern of relationships among scores on these two sets of scales with chronological age and Bayley physical age, support the claim of the model that a specific cognitive structural base underlies developments in the social-communication and object domains, as operationalized by the assessment instruments. (Author/MP)