Executive producers Rich Appel and Alec Sulkin noted that this is Stewie's "first word" only in the traditional sense that parents document words they actually understand; technically, it is his 1,345,693th word .
The most interesting feature of the Season 19 premiere, is that it addresses one of Family Guy's longest-running meta-jokes: whether the family can actually hear or understand Stewie . [S19E1] Stewie's First Word
In this episode, Stewie shouts a ("F--k") during a church service after learning there are no cookies. While he has been speaking fluently since the series began, this was the first time his speech was clearly understood by everyone in the room. Key Meta-Features & Trivia Executive producers Rich Appel and Alec Sulkin noted
A major subplot involves Lois binging the children's show Caillou , fearing it taught Stewie to swear, which served as a vehicle for the writers to mock the real-world cartoon's perceived bad influence. While he has been speaking fluently since the
When Brian asks why everyone can suddenly understand him, Stewie explains that the "intense emotion" of the moment (his cookie-related rage) caused the word to "burst through" his usual baby babble.
Later in the episode, Stewie says a second audible word— "Mommy" —suggesting a rare moment of affection for Lois, though he refuses to repeat it for her camera.
Watch the specific moment Stewie's outburst shocks the entire congregation: Stewie Says His First Word - Family Guy 19x01 Blow Up Your Humor YouTube• Sep 28, 2020 YMMV / Family Guy S19E1 Stewie's First Word - TV Tropes