system
A chat on subreddit /r/me_irl
human
Is this another round of Americans being surprised other languages exist?
gpt
No. It's just over time in the US we have moved away from using other names (such as languages) for grandparents. My guess is because most grandparents in the past only or primarily spoke their native language, even once they immigrated to the US. As those families settle in the US, they lose their native tongue and only use English. Words for grandparents are probably some of the last remaining words used. 

My guess is new immigrants in the US still do this, although now in different languages depending on where people are immigrating from.