puirt-a-beul

"'Mouth music' is known by many different names: cheek music, chin music, lilting, diddling, gobbing, reel ˆ bouche, port-a-beul. It is built on favorite old melodies and rhythms and used for making music -- for dancing -- when there are no instruments to play. They are not songs but instrumental tunes whose lyrics power the rhythm.It can be found in various forms throughout the world, but it is highly developed among the Gaels. It became part of the musical baggage of Scottish and Irish emigrants and traveled with them to Nova Scotia and down into the southern Appalachians. The term "mouth music" is likely to be a translation of the Scots-Gaelic "port-a-beul" ("tunes from the mouth"). It is sometimes sung with sparse instrumental accompaniment (bones, bells, drums) but is mostly unaccompanied. It was used as dance music and to make work lighter. Lilting is part of a larger tradition in Ireland, called "sŽan nos" or "old style." It emphasizes subtle ornamentation and embellishment in song" - from Rambles, a cultural arts magazine

Human beat box, basically.

So "Buffalo Gals" - Appalachian square-dance caller meets Bronx MCing - was really onto something.