Yoder & Warren: Maternal Responsivity 1207 Journal of Speech, Language, and Hearing Research Paul J. Yoder Steven F. Warren Vanderbilt University Nashville, TN Family systems theory posits that the relative effectiveness of early interventions will vary depending on various aspects of the family. This study tested whether maternal responsivity would predict the extent to which Prelinguistic Milieu Teaching (PMT) facilitated generalized intentional communication better than a contrast treatment that was conducted in a small group by a responsive adult (i.e., Responsive Small Group, RSG). Fifty-eight children with developmental disabilities in the prelinguistic communication period of development were randomly assigned to one of the two staff-implemented treatment groups. Thirty were assigned to RSG; 28 were assigned to PMT. Mothers were kept naive to the intervention methods, hypotheses, and measures. In families with mothers who responded to a high percentage of the children’s communication acts at the pre- treatment period, the children in the PMT group used more frequent intentional communication in post-treatment generalization sessions with a trainer and mothers than did children in the RSG group. In the families with mothers who responded to fewer than 39% of their children’s communication acts, children in the RSG intervention used more frequent intentional communication in post- treatment generalization sessions with the mothers than did children in the PMT intervention. Other family variables and no child variables that we measured could account for these findings. KEY WORDS: mother-child interaction, prelinguistic communication, interven- tion, children with developmental disabilities, systems theory Maternal Responsivity Predicts the Prelinguistic Communication Intervention That Facilitates Generalized Intentional Communication JSLHR, Volume 41, 1207–1219, October 1998 ©1998, American Speech-Language-Hearing Association 1092-4388/98/4105-1207 Journal of Speech, Language, and Hearing Research 1207 W hen faced with a nonverbal client, many clinicians may be tempted to try to teach the child to talk. However, there is good reason to expect that sufficient neurological matura- tion is necessary for language intervention to be effective (Wakefield & Wilcox, 1995). For example, Wilcox and colleagues posit that sufficient myelination and synaptogenesis in the prefrontal cortex must have oc- curred before children can make sound–meaning associations. There- fore, it is not surprising that attempts to teach language to children with developmental disabilities who are not yet talking have largely been unsuccessful (e.g., Girolametto, 1988). As an alternative to teaching children to talk, Yoder and Warren (1993) suggested that we enhance children’s ability to use the type of