Maggie 's squeaking and occasional speaking parts are currently provided by Nancy Cartwright , but she have also been voiced by guest stars James Earl Jones , Elizabeth Taylor and Jodie Foster , and by series regulars Yeardley Smith and Harry Shearer . Maggie have appeared in various media relating to The Simpsons – including video games , The Simpsons Movie , The Simpsons Ride , commercials and comic books – and have inspired an entire line of merchandise .