From a sociohistorical point of view, we stress that children acquire language through involvement in verbal interaction and in joint activity with other more competent language users. The goal of this paper is to compare the educational strategies used by mothers of young children with Down Syndrome in their linguistic interactions with their children, and those used by the therapist during a period of language intervention. Muny significant differences were found. Compared with the strategies used by the therapist, the strategies used by the mothers could not be considered optimal for language development. The optimal difference between the language the therapist addresses to the children and the complexity of their utterances enhances their inorphosyntactic development.