Increasing spontaneous verbal responding in autistic children using a time delay procedure.

One oft-cited problem with teaching speech skills to autistic children is the failure of the speech to be spontaneous. That is, the children's speech often remains under the control of the verbal behavior of others rather than under the control of other nonverbal referents in the environment. We investigated the effectiveness of a time delay procedure to increase the spontaneous speech of seven autistic children. Initially, the experiment presented a desired object (e.g., cookie) and immediately modeled the appropriate response "I want (cookie)." Gradually, as the child imitated the vocalization, the experimenter increased the time between presentation of the object and the modeled vocalization in an attempt to transfer stimulus control of the child's vocalization from the experimenter's model to the object. Results indicated that all the children learned to request items spontaneously and generalized this behavior across settings, people, situations, and to objects which had not been taught. These results are discussed in relation to the literature on spontaneous speech, prompting, and generalization.