I use Ubuntu-Gnome 13.04 and I can't change system language.
I set it to Polish with "language & regions".
It was though because there is no option for adding so i installed:
language-pack-pl
language-pack-gnome-pl
then i could pick it in "language & regions" and then reboot.
However this didn't solve my problem
I also change it with gnome-language-selector and still got english.
Please help, because if the language is other than polish i will have to switch back to windows.
I like the gnome3.