Thirty deaf children admitted to an auditory training program before age 2 were studied longituninally to age 40 months in an investigation of the effectiveness of early intervention, the relationship between mother-child interaction and language acquisition, and the effectiveness of new devices developed for auditory training. Among findings were that Ss admitted prior to 16 months old showed greater language competence and that mothers of Ss with better language skills were less coercive and more sensitive and accepting to their children. Affective aspects of mother-infant interaction were more highly correlated with the child's language aquisition than were technical aspects of the mother's language. Devices developed to reinforce vocalization and to stimulate receptive language in Ss from deaf homes included a sound activated mobile and a Teddy bear. Problems such as technical difficulties and insufficient child interest led to the conclusion that the devices were of limited value. Subsequent experiments which provided direct auditory and speech training services to deaf parents seemed more promising. (Appendixes include the Lexington Preschool Oral Language Assessment, Mother-Infant Communication Rating Scales, and diagrams of the auditory training devices.) (LS)