It does do it for them. If you buy a computer in Denmark, it has a Danish keyboard, complete with regional symbols, you can buy Spanish keyboards as well. There are character codes for those on an American keyboard. But there are different regional keyboards. Computer languages on the other hand are mostly if not all in English. Microsoft is infuriating though, you have to pay extra for regional settings. I am not sure for Apple but I imagine it is much the same. Other operating systems come in all sorts of languages though. Anyway, yes there are regional keyboards.
you change the language on the computer.
some computers has two languages on the keyboard
yeah, same with cell phones