Gibb Sahib, thanks for your contribution to this thread. I don't think your post was off-topic at all.

The information is very interesting. I intend to spend some time studying it.

As for why "mama" is the target of so many insults throughout the world, I think this is partly because who a person's father is might be questionable, but (except in cases of foster care/adoption and other similar cases) a person always knows who her or his mother is.

Also, I think that part of the reason for mothers being targeted bt insults is tied to the importance of mother in matriarchal societies.

In addition, I want to note that certain contemporary in-your-face children's playground rhymes, it's not just mothers who are targated by insults but grandmothers. Note the examples in this thread of "bald headed grannie" who goes out with Frankenstein. That line contains two insults-1. your grandmother is bald-headed and 2. your grandmother dates someone as ugly as Frankenstein. Not to mention that grandpa's not in the picture...but that's another story.

And for what it's worth, these rhymes are usually performed in the USA as two, three, or four person handclaps.