I wonder why specifically those languages. Were only those markets using localized file names and everyone else sticking to English?
Or was it just random chance, i.e. some setup programs from those locales happened to cause issues and got escalated, so those names got on the list?
Maybe many other languages were already covered by "inst" due to common language roots or just straight up borrow "setup" or "installer" from English because there was no established localized term.
In 95 localization was scarce. Also, the partial "inst" would have matched "install" translated to several languages (about 15 by my quick count, could be more).