Thats the term Stallman came up with when the first distributions (esspecially Debian) started to build up. It wasnt really popular even back than so he setteled in GNU/Linux as alternative which to this day is in the name of quit a lot distributions.
It was never the plan/intend to rename the Linux kernel itsself to either of those terms.
As a Bavarian I grew up with the German set but I myself prefer the french one. Don’t know why, I guess I just like it‘s style/asthetics more.
Didn‘t new about the Italian and Spanish ones until today.