No I didn't understand that, since aunt and uncle doesn't mean that in my language. I thought it was just parents sister and brother, I didn't know that parent in laws were also considered aunts and uncles.

I guess I’m trying to say it doesn’t need a word to understand those are similar positions on a family tree. We happen to have words for that in English but even if you didn’t I’d think you’d realize these people are related to you in similar ways - I could be wrong and that’s not obvious, I figured it would be but I can’t deny my ignorance of how other cultures think about things and how their languages effects that

That's not very convincing. My mother and my mother-in-law are both grandma to my children, but I doubt many languages use the same word for them.

uncle/aunt is wildcard relation and means little. Actually in Russian for example it is the same word you use to describe a random person whom you may not even have any relation to

There's a lot of languages where aunt/uncle is just a polite word that children can use to refer to older adults who are not their parents (in some languages there is an upper age limit, where it becomes polite to refer to these as grandma/grandpa).

And some languages where all the different varieties of father's brother's wife have their own distinguishing names, but then there's also a generic term which means 'older person of one gender who usually comes to the house on $HOLIDAY'.

The children have nothing to do with that for a start. They may not even exist.

They don't have to, the point is they occupy the same relative position in the family and I chose to illustrated that using a child