Marge recounts how Lisa first spoke as the family awaits baby Maggie’s first word.
The Simpsons try to coax Maggie to say her first word. Homer tries in vain to get Maggie to say “Daddy,” but he only gets her to burp. Thinking back to Bart’s first word, Marge recalls a young Bart uttering “Aye carrumba,” after walking in on she and Homer in bed. Lisa asks what her first word was and Marge drifts back to 1983, when she first learned she was pregnant with Lisa… With the arrival of their second baby, Marge convinces Homer it is time to look for a bigger house. While they house hunt, Bart stays with Patty and Selma. They dote over Bart, lavishing him with attention.
The year 1983 gives way to 1984 and the Summer Olympics. A Krusty Burger promotion offers free burgers for events that the U.S. wins. The contest is rigged so only sports where the Russians dominate are part of the game. During that time, the Russians boycott the Olympics. While Marge puts on weight going into her ninth month, Homer puts on weight eating hamburgers he has won.
When Lisa finally arrives, Bart has a difficult time making the adjustment. Jealous of all the attention being heaped on the new baby, Bart wishes Lisa was never born. He decides to run away. Lisa toddles into his bedroom and says her first word: “Bart.” Bart feels honored. Marge tells Bart that Lisa loves him very much. Reconsidering the downside of having a little sister, Bart decides to not run away. Homer tries to get Lisa to say “Daddy,” but she can only say “Homer.” …Back in the present, Homer carries Maggie up to bed. Turning out the light and leaving Maggie alone, she utters her first word: “Daddy.”
Source: 20th Century Fox