Can't change language from English

Hi there,

I'm trying to change the language of my Gallery 2.3.1 but without luck.

In the admin section I have set the Default language to Swedish. I've also tried doing the same for various users but to no avail.
I've even tried:
http://localhost/gallery2/main.php?g2_langauge=sv
but its still in English

The funny thing though is that the Upgrade section is displayed in Swedish, that is the page:
http://localhost/gallery2/upgrade/index.php

At the same time, this is in English:
http://localhost/gallery2/install/index.php

I've tried on both my laptop with Ubuntu and a QNAP NAS 259 Pro+ Server.

I have the files:
/var/www/gallery2/locale/sv/LC_MESSAGES/gallery2_install.mo
/var/www/gallery2/locale/sv/LC_MESSAGES/gallery2_upgrade.mo

in the locale folder.

Any ideas what the problem is? How might I fix it if I'm not afraid to get my hands dirty with a bit of Php?

Thanks,

Barry

Thanks for the reply, multi-language was installed.

I installed the Swedish locale via:

sudo apt-get install language-pack-sv-base

and now it works! Wonder what the equivalent is for the NAS Server...