This study examined the effectiveness of matrix-training procedures in teaching action + object utterances in both the receptive and expressive language modalities. The subjects were 4 developmentally delayed preschool boys who failed to produce spontaneous, functional two-word utterances. A multiple baseline design across responses with a multiple probe technique was employed. Subjects were taught 4-6 of 48 receptive and 48 expressive responses. Acquisition of a word combination rule was facilitated by the use of familiar lexical items, whereas subsequent acquisition of new lexical knowledge was enhanced by couching training in a previously trained word combination pattern. Although receptive knowledge was not sufficient for the demonstration of corresponding expressive performance for most of the children, only minimal expressive training was required to achieve this objective. For most matrix items, subjects responded receptively before they did so expressively. For 2 subjects, when complete receptive recombinative generalization had not been achieved, expressive training facilitated receptive responding. The results of this study elucidate benefits to training one linguistic aspect (lexical item, word combination pattern) at a time to maximize generalization in developmentally delayed preschoolers.