"BTW, the taunt that I remember doing and still hear African American children say is more like "Nah nah nahnahnah."

I've never added or heard anyone else {African American} add a "boo" at the end of this taunt. Of course, this doesn't mean that there are no African Americans who add "boo" to Nah nah nahnahnah {or however it is said}. What it means is that no Black kids I know or heard have done it. I'm referring here to African American children living in all or predominately Black neighborhoods."

Late to the party here, but the first time I heard anybody in real life (not in a book or on TV, I mean to say) add a boo-boo (actually a poo-poo) was my (biracial) niece.

I'm white, in NYC. Growing up I said "nyah nyah na nyah nyah". Starting in my teens (so about a decade ago) I started hearing teens affecting kid speech going "na na na na na" instead.

And then we all grew up, and the next thing I know my little five - no, make that six now - year old niece is teasing the kids on the block with "nanny nanny poo poo" and correcting ME! But I don't know where she got her version from. Her parents are unlikely to indulge in children's taunts, and her school is a bit of a rarity and genuinely mixed - in her class of 24 you can divide it fairly evenly between black kids, white kids, and Hispanic kids. There's even a sizeable amount of other biracial (black and white, that is) children there, as well as a few Arab and Asian children (though not as many as I'd expect, given our neighborhood). (It's a very small school though, just opened this year, so we'll see if this keeps up in future years.) So she could have gotten it from *anybody*, you know? It might still not be a commonly done thing with most African American children except in her school.