walla
n.— «Gone are the days when actors would stand around muttering nonsense syllables, such as “walla walla,” to approximate conversation—hence the term “walla” to describe the effect.…”I might say to my group, “Now we’re going to just do a “walla bed.”» —“Walla Sound” by Wenzel Jones Backstage Aug. 5, 2005. (source: Double-Tongued Dictionary)