This is the problem: every language is an exclusive cultural club. I want to have one that isn't an exclusive cultural club.
> I learned things that simply can't be translated into other languages without long paragraphs of explanation that would actually require the reader to accept some knowledge of the language to understand them
What would be an example of this? For example in Korean there's the concept of 정, which is a Korean-specific feeling of love/loyalty/bond with another person. You could write paragraphs about how it's subtly different from Japanese Jyo or English love/loyalty/bond, but at the end of the day either you need the concept and create a word for it in the global language, even "Jeong" or whatever, or you don't need the concept and don't create a word for it.
You don't build all of FORTRAN into CSS just because you want to borrow the concept of variables. You borrow what you need and make sure it fits nicely with what's already there.
> And people who grew up speaking this language have their entire life experience wrapped up in it, and their entire family history wrapped up in it for thousands of years.
You're saying that if over a generation they were to switch from one language to another their children and grandchildren would be without a history?
The children in our family don't speak the same language as their grandparents did. They don't know any of the culture-specific words. This doesn't seem to matter in any way that I've noticed, and certainly they themselves haven't.