tra la la bim bom

An interesting question popped up on a musicology listserve:

Is there a word that means/describes sung nonsense syllables like "tra la la" or (in the case of Jewish folk song) "bim bom"? I'm looking for some way to refer them as a group other than just as "the nonsense syllables."

I thought it was referred to as sing-song.

There's a Jobim song called Bim Bom.