Change Squirrelmail language
When you try to change the language of SM you'll probably get a little disappointed - nothing changes.
The explanation is quite simple, the localization files aren't installed by default, and apt-get isn't your friend as EHCP doesn't use a package manager to install SM, but instead uses a customized set of files.
But don't despair. It's actually quite easy to install extra locales.
Firstly make sure that you've got the needed packages:
apt-get install bzip2
Then create an empty directory, and download the desired language pack here.
Extract the language pack. You need the correct character set installed. Check the extracted file setup.php (look for the line $languages['xx_XX']['LOCALE'] = array('xx_XX.ISO8859-1',...) to make sure which set is used in the locale file. If missing, or in doubt run the following command, and check the necessary sets:
Run the install script:
It will ask for your path to your squirrelmail installation:
Change to the directory containing the compile scripts:
First compile the locale:
To be on the safe side, restart your webserver:
After changing your language (Options > Display Preferences > Language > Submit) you have to click "Refresh Page", and you're done.