Journal of Speech and Hearing Research, Volume 37, 841-851, August 1994 Facilitating Prelinguistic Communication Skills in Young Children With Developmental Delay II: Systematic Replication and Extension Paul J. Yoder Steven F. Warren Kyoungran Kim Gail E. Gazdag John F. Kennedy Center Vanderbilt University Nashville, TN Four children with mental retardation were studied in the context of a multiple baseline across subjects design. Staff members used a modified version of the milieu teaching method to facilitate intentional requesting. The results replicated the finding that a modified version of milieu teaching was effective in facilitating the use of intentional requesting by children with developmental delays in an intervention context (Warren, Yoder, Gazdag, Kim, & Jones, 1993). This study also extended the Warren et al. (1993) work by (a) documenting that increased intentional requesting generalized to sessions with the children's mothers, (b) demonstrating that mothers who were naive to the purposes of the study were more likely to linguistically map their children's prelinguistic communication after the intervention than before the treatment, and (c) that mothers and teachers who were naive to the purposes of the study linguistically mapped the children's intentional communication more than the children's preintentional communication. We discuss implications of these results for early intervention, the transactional theory of development, and the importance of the distinction between intentional versus preintentional communication. KEY WORDS: children with mental retardation, prellnguistlc communication, Interven- tion, linguistic Input, mothers The present study attempted to replicate the findings of Warren, Yoder, Gazdag, Kim, and Jones (1993) that a modified form of milieu teaching facilitated increases in children's prelinguistic requesting in intervention sessions with staff members. Addi- tionally, the present study attempted to extend the existing support for modified milieu teaching by demonstrating that child intentional requesting generalized to sessions with the subjects' mothers, who had been kept naive of the details of the study. Data were also collected to document the transactional effects of the intervention. This was done by observing whether the subjects' mothers increased the frequency and proportion of child communication that they linguistically mapped. Finally, we tested whether linguistic mapping, one type of language-facilitating behavior, was used more often after intentional prelinguistic communication acts than after preintentional acts. The term linguistic mapping of child communication is used to refer to the adult verbally marking what the child is communicating nonverbally (Warren et al., 1993). For example, if a child reached for a cup and then looked at a teacher, the teacher's verbal response of "You want the cup" is a linguistic map of what the child intended to communicate. Linguistic mapping of child communication may be particularly likely to facilitate vocabulary development because a child is already attending to the © 1994, American Speech-Language-Hearing Association I~~~~~~~~~~~~~~~~~~~~~~ 841 0022-4685/94/3704-0841