Yeah, I think it's an uncommon word. It's not a concept that would come up for most American English speakers, unless you're in a community that uses a language with another writing system (I think I first encountered it in a synagogue with Hebrew) or you're learning such a language.

I think I've maybe occasionally seen "translit." in text used to mark that the following is transliterated, but I could see that being easily glossed over.

I don't think so, but I grew up before cell phones and AI so I had to learn how to read. I'll leave the explanation for the rest who skip over the guillemet at the beginning like I did.

Not imo. It's a word that I would expect any adult who finished college to have seen before.

I only know it because Im bilingual