In the interview, O’Brien recalled the arguments in the writer’s room as to the spelling of Homer’s eminent ejaculation. O’Brien said that many members of the staff wrote it as the now commonly accepted “d’oh!,” although some writers spelled it out as “doe,” which both O’Brien and Castellaneta thought to be a mite risible. “A female deer,” Castellaneta jibes. Castellaneta, however, recalls first encountering the phenomenon in an early script — back when “The Simpsons” was an animated segment on “The Tracy Ullman Show” — when it was written down simply as the voice direction [annoyed grunt].
Indeed, it seems that, even to this day, ‘d’oh!” is written in scripts as [annoyed grunt]. Groening left it up to Castellaneta as to what an [annoyed grunt] would sound like. Castellaneta, digging deep into popular culture, remembered a famously put-upon character from old Laurel and Hardy short films played by comedian James Finlayson. Finlayson had a peculiar annoyed grunt of his own, which Castellaneta imitated. It’s a “d’oh,” but it’s more of an angry “da–!,” cut off by a glottal stop, and followed by an annoyed, quieter “oooh!” The “Da–” part was, Castellaneta pointed out, a way for the character to avoid saying “damn” on 1930s TV. “D’oh” is, then, a “damn” interrupted by an “Oh!”
O’Brien gleefully points out that saying “damn” on television doesn’t seem to be an issue any longer, as Castellaneta had just said it openly. Castellaneta prods back with a “F’oh!”