Whether or not the teachers or adults hear what the kids say, the kids still say them.

Back in the middle 1950s we "students" at a Catholic grade school in west central Illinois sang "Glory, glory, halleuia, teacher hit me with a ruler...." in several variants. We sang about the burning of the school, too.

And we insulted each other in ways such as these:

Boy: You know, I don't care for your perfume.
Girl: I'm not wearing any.
Boy: Oh.

You know, you don't sweat much for a fat boy/girl.

Your momma puts a bag over your head to kiss you goodnight.

(At lunch) Oh, you're eating a butter sandwich. Gee, I'm sorry, I was wrong...I guess it's snot.

Do you think you'll get into heaven if you keep that bag over your face? Jesus don't want ugly kids up there.

And worse...much worse. And 99% of us turned out okay.