A study examined the differences between 17 children with language disorders and 20 children with normal language development (ages 8-13) in the way they developed shared knowledge with an adult using an interactive communication task. The structure interaction map task involved the child describing a route through a simple schematic map to an adult who had a similar map, but without a route. Subjects were informed that the listener's map was slightly different from their map and they could not view the listener's copy. Five maps were used with a number of pictorial features relevant to describing the route. For each map, the adult introduced questions about features that were nonexistent on the subjects' map. Results found that there was a significant difference in the verbal productivity between the group of children with normally developing language and those evidencing language disorders. No significant differences were found in the number of conversational turns attempted, the number of features named, or the expansions. Using a discriminant function analysis, however, 75 percent of the children with language disorders could be correctly classified based on performance on the 4 variables of expansions, features named, words spoken, and conversational turns. (Contains 12 references.) (CR)