Perhaps what is most distinctive about the music in "Another Brick in the Wall, Part 2" are its un-Pink Floyd aspects.
The band was often labeled as acid rock in its early years and also showed a willingness to dabble in R&B and even country. The band would come to be defined by its cutting edge psychedelic sounds, which when combined with a tendency toward the thematically dark and gloomy, produced strictly made-for-adult music. But "Another Brick in the Wall" rests on a surprisingly trendy disco beat, and the vocals in the second half of "Brick in the Wall" are provided by a children's choir.
Both of these surprising elements can be laid at the feet of Bob Ezrin, who was brought in to produce The Wall in 1979. Ezrin was already thinking about making a single, so he sent Dave Gilmour out to some disco clubs to get a feel for the trendy rhythms. It almost backfired. "I forced myself out," remembered Gilmour, "and listened to loud, four-to-the-bar bass drums and stuff and thought, Gawd, awful!" But the band eventually went along with the idea "so it would be catchy." (Source)
The song, as recorded, was too short for a single, and the band was not interested in recording a second verse, or even producing a single for that matter. So, Ezrin also came up with the idea of having a school choir sing the second verse. Ezrin, who had recently produced Alice Cooper's "School's Out," had an engineer find a local choir to record the track.