Nowadays, walla actors make use of real words and conversations, often improvised, tailored to the languages, speech patterns, and accents that might be expected of the crowd to be mimicked.
In an episode of Harvey Birdman Attorney at Law, a distraught courtroom audience distinctly and repeatedly shouts "rutabaga", a reference to the use of the term "rhubarb".
In the film Blazing Saddles, Mel Brooks's character urges attendees at a meeting to "harrumph", to the point of singling out a man who did not say it.
While it is generally expensive for the film makers to put distinct words in a specific background performer's mouth (as this would turn "extras" into actors during the sound mix, meaning they must be paid more), this problem can be avoided by recording gibberish that syncs with the on-screen mouth movements ("lip flap") of a specific background performer.
In the Anthony Newley–Leslie Bricusse 1961 musical Stop the World – I Want to Get Off, the main character, Littlechap, is campaigning for elected office as a member of the Opportunist Party and makes speeches, all of which start with "Mumbo Jumbo".