The song "Kumbayah" popped into my head the other day... and what else did I do but Google it to get more information on this word.
Firstly - you DO know the song, right? sung to the same tune as "Michael rows the boat ashore, hallelujah", this song goes "Kumbayah, my Lord, Kumbayah". I have no idea how i picked up on either song, but hey, i am a hippie at heart, and kumbayah is something i associate with doped up 60's people in flowing white robes ;-)
aaaanyways... it seems that it actually stands for "Come by here". Cool, eh?
The language is "Gullah", which is a creole consisting of English plus words and constructions from the languages of west Africa, the Gullahs' homeland.
"Creole", among other things, means "a language that has evolved from a pidgin but serves as the native language of a speech community" (thanx, www.m-w.com!)
Read more about Kumbayah itself here, and about the Gullahs here.
Have an educational day!