Very little research has focused on the development and evaluation of intervention strategies designed to facilitate the acquisition of prelinguistic communication skills. We conducted two experiments to determine the effects of a milieu teaching approach on the acquisition and generalization of specific prelinguistic communication skills. In the first experiment, we utilized this intervention approach within a multiple baseline design to teach prelinguistic requesting, commenting, and vocal imitation to a single subject with Down syndrome and language delay. The results indicated that the intervention approach was effective at facilitating the child's use of these skills within the treatment setting. Therefore, in the second experiment we conducted a more comprehensive analysis of this approach with 4 subjects with mental retardation. Three of these subjects were taught to request, and 1 subject was taught both to request and to comment. The effects were experimentally evaluated with multiple baseline across subjects design. The results indicated that the intervention was effective in eliciting the intervention targets within the training setting for all 4 subjects. All 4 subjects showed evidence of generalization across stimulus materials, setting, teachers, and interaction style. There was also evidence of reciprocal effects on how classroom teachers in the generalization setting interacted with the subjects as a result of changes in the child's communication behavior.