Dan Castellaneta, Julie Kavner, Nancy Cartwright, and Yeardley Smith all began voicing their characters on The Tracey Ullman Show. Nancy Cartwright was the only one of the group who had been trained to be a voice actor while Castellaneta had done some voice over work in Chicago. Castellaneta and Kavner had been part of the regular cast of The Tracey Ullman Show and voices were needed for the shorts, so the producers decided to ask them to voice Homer and Marge rather than hire more actors. The producers decided to hold casting for the roles of Bart and Lisa. Yeardley Smith had initially been asked to audition for the role of Bart, but casting director Bonita Pietila believed her voice was too high. Smith later recalled, "I always sounded too much like a girl. I read two lines as Bart and they said, 'Thanks for coming!'" Smith was given the role of Lisa instead. On March 13, 1987, Nancy Cartwright went in to audition for the role of Lisa. After arriving at the audition, she found that Lisa was simply described as the "middle child" and at the time did not have much personality. Cartwright became more interested in the role of Bart who she found more fascinating because he was described as "devious, underachieving, school-hating, irreverent, [and] clever. " Matt Groening let her try out for the part instead, and upon hearing her read, gave her the job on the spot.