Wiki Default language change

[irgenetics]

I have successfully installed mediawiki 1.4.11, I need to change the default language which is english to farsi(persian). I am able to do it through preferences, but as soon as I log out the language roll back to english. does anyone know how to change the main language to languages other than english permanently?

[Jediarchives11]

I believe that you have to set it in localsettings.php.
Find the line: $wgLanguageCode = "en";
Then change the en to the appropriate language code for farsi.