We compared strategies to teach vocal intraverbal responses to an adolescent diagnosed with autism and Down syndrome. One strategy involved echoic prompts only. The second strategy involved an echoic prompt paired with a modeled prompt in the form of sign language. Presenting the modeled prompt with the echoic prompt resulted in faster acquisition of correct responding. Results are discussed in terms of using functional stimulus classes to facilitate vocal intraverbal acquisition with learners who have a history of sign language training.