A program of projects will be conducted to better understand the requisites to initial language skills so as to enhance language learning by mentally retarded humans. The projects include a feasibility study with eight retardates at the Georgia Retardation Center to assess the merits of the computer-based system developed as part of the LANA Project at the Yerkes Regional Primate Research Center, a study program with four chimpanzees to assess the chimpanzee as an animal model for language-relevant studies which cannot be conducted with children because of ethical constraints, and continued work with Lana chimpanzee to assess the limits which might characterize language learning by chimpanzee subjects.