To gain some insight into the problem of deviant speech development in low income populations, this study investigated the environmental factors that encourage the development of normal speech. Two specific questions were examined in this study: (1) If specific vocalized environmental sounds are presented contiguously with reinforcement, will subject vocalizations of that sound increase? and (2) Would establishing specific environmental sounds as discriminative for reinforcement produce increases in subject vocalizations of those sounds? Subjects were a 13-month-old female and a 10-month-old male. Experimental manipulations involving recording of environmental sounds and a stimulus presentation tape established the conditions in question: specific vocalized environmental sounds presented contiguously with reinforcement and specific environmental sounds established as discriminative for reinforcement. Findings indicated that, for these subjects, pairing sounds with reinforcement produced no effects on rate of vocalization of these sounds, but that making these sounds discriminative for reinforcement did increase subjects' rate of vocalization. (MH)