Maggie Simpson Maggie's occasional speaking parts and other vocalisations are currently provided by Nancy Cartwright, but she has also been voiced by guest stars James Earl Jones, Elizabeth Taylor and Jodie Foster, and by series regulars Yeardley Smith and Harry Shearer. Maggie has appeared in various media relating to "The Simpsons" – including video games, "The Simpsons Movie", "The Simpsons" Ride, commercials and comic books – and has inspired an entire line of merchandise. "The Simpsons" uses a floating timeline in which the characters do not physically age, and as such the show is assumed to be set in the current year.
The Simpsons success of "The Simpsons" and the lower production cost prompted US television networks to take chances on other adult animated series. This development led US producers to a 1990s boom in new, animated prime-time shows for adults, such as "South Park", "Family Guy", "King of the Hill", "Futurama" and "The Critic". For "Family Guy" creator Seth MacFarlane, ""The Simpsons" created an audience for prime-time animation that had not been there for many, many years ... As far as I'm concerned, they basically re-invented the wheel. They created what is in many ways—you could classify it as—a wholly new medium." "The