how do I set user locale with Fedora 17?

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http://forums.fedoraforum.org – I have set the default language to Serbian and it hence the login page is now in Serbian Cyrillic. However today I logged out and when Iogged in everything had reverted to US English. I normally use LXDE but I logged into Gnome and that is now also in English. I don't understand what I changed but keyboard crashed just before (which is why I logged out). running locale from a terminal gives me: ~\>locale LANG=en_US.utf8 LC_CTYPE="en_US.utf8" LC_NUMERIC="en_US.utf8" LC_TIME="en_US.utf8" LC_COLLATE="en_US.utf8" LC_MONETARY="en_US.utf (HowTos)