Lisa's First Word Bart was two during the flashback. Maggie's first word was provided by the Academy Award-winning actress Elizabeth Taylor, who would also voice herself in the season four finale, "Krusty Gets Kancelled". While promoting the episode, the producers initially did not reveal who the voice of Maggie would be, prompting speculation as to the identity of the actress. Although it was only one word, the voice came out "too sexy" and Taylor had to record the part numerous times before the producers were satisfied and thought it sounded like a baby. Several sources, including John Ortved's "The Simpsons" history article "Simpsons
The Simpsons (season 21) technically counts as a component of the 20th production season (and of the 21st broadcast season). It does not, however, count towards the series' official animated episode count (i.e., it is not episode 452). The Simpsons (season 21) "The Simpsons" twenty-first season aired on Fox from September 27, 2009 to May 23, 2010. It was the first of two seasons that the show was renewed for by Fox, and also the first season of the show to air entirely in high definition. With this season, "The Simpsons" established itself as the longest-running American primetime television series surpassing "Gunsmoke". The season