"The Ballad of Buzz Cola" is the only Stephen Sondheim song in which he doesn't get credit for the lyrics.
Peter Bogdanovich parodies his role from The Sopranos (1999) in this episode, as a therapist to another therapist.
During an April 1, 2020, interview on "Putting It Together" (Kyle Marshall's podcast about Stephen Sondheim's work), the writer of this episode, Michael Price, described how he got Stephen Sondheim to appear as a voice actor in "Yokel Chords." A longtime Sondheim fan, Price was developing the story when he went to a birthday party for Liz Berman, the wife of Star Trek: The Next Generation producer Rick Berman (Price's wife and Liz Berman are friends). There, Price met the playwright and screenwriter John Logan, who had collaborated with Rick Berman on Star Trek: Nemesis and who was at the time of the party working with Sondheim on the screenplay for the Tim Burton movie adaptation of Sweeney Todd. Price, awed, asked Logan if he thought Sondheim would ever agree to appear on The Simpsons, and Logan suggested that Price should write Sondheim a physical letter asking him that question; Logan gave Price Sondheim's home address. Price spent two days composing the letter to "make sure it sounded smart and nice and not too fawning, because I pretty much could have just gushed all over the place." A few weeks later, Price received a type-written response from Sondheim saying that he would be interested in doing the episode. Price recounted, "then they flew me out to New York to meet him and to be there for his recording, and through kind of a happy accident--for me, probably not for him---there was a mistake made with the recording studio. Because he had some dialogue--there's a short dialogue scene where he meets Krusty and as The Simpsons will often do with a celebrity, we kind of wrote like an ironic version of the character, so in this version he was like a young, eager guy handing these songs to Krusty, because Krusty had hired him to write songs for this TV special.... Then he had to play that little song, and there was a piano for him. But there was a mistake with the studio, so the piano wasn't ready. So he agreed to come back a second day. So on Wednesday, we did his dialogue stuff, and then he came back on Thursday for like twenty minutes. And he sat there at a concert grand piano and played that little Buzz Cola song and then I think he added that 'With lemon!' part, I think that was his ad lib.... He did it like two or three times, and then I said, 'Okay, can we just get one version where it's just the piano part, in case we need that,' and he goes 'okay, okay.' He was very nice about the whole thing. Then he said, 'Okay, are we done now?' And I said, 'yeah, actually we are, but only one last thing...could you now please play for me the entire score for Sweeney Todd?' And he started laughing and he was like, 'no, no,' but then he put his hands on the keys and started playing! And I was done. I could die now."
The Sound of Music, the musical that is the main subject for parody in this episode, was written by Richard Rodgers (music), Oscar Hammerstein II (lyrics), and Howard Lindsay and Russel Crouse (book). Stephen Sondheim, a guest star in this episode, knew both Hammerstein and Rodgers well: when he was a child he and his mother moved into a house in Pennsylvania near the Hammersteins. Young Stephen became friends with their son but also developed a surrogate father-son relationship with Oscar Hammerstein, who also taught him how to write for the musical theater. Through that relationship, Sondheim met Richard Rodgers and collaborated with him on the musical Do I Hear a Waltz?; he also became lifelong friends with Rodgers's daughter Mary, herself the author of the Broadway musical Once Upon a Mattress and such children's books as Freaky Friday, Summer Switch, and A Billion for Boris. Sondheim based the character of Mary Flynn in Merrily We Roll Along on Mary Rodgers.
According to Spucklers' family tree, Brandine Spuckler is Cletus's daughter.