The study evaluated whether specifically language impaired (SLI) children (N=6 and ages 5-8) manifested atypical or normal but delayed development in their interpretation of PRO (an empty pronomial element which has also been termed "a missing complement subject"). Language samples were taken and analyzed twice over a 9-12 month period. Among conclusions were: some SLI children may manifest developmental stages characteristic of normally developing children; these children may go through the same developmental stages but at later ages; longer time intervals are required for change and response patterns may be unstable for this population; for some SLI children, mixed and unclassifiable response patterns may persist into early childhood; and there is a need for a large scale study of SLI children's interpretation of PRO. (Includes 20 references.) (DB)