You can download new language packs from SWsoft site and install them to the control panel. The number of languages you can use with your control panel depends on the license key you purchased. The control panel will alert you when you attempt to install more languages than allowed.
To view the interface languages installed in the control panel:
Note: you can make a language not available to control panel users. To do this, click an icon . To make a language available to users, click an icon
.
To install a new language pack that you downloaded from SWsoft web site:
To uninstall a language pack from the control panel:
If the language pack you have just removed is used by some other users, their interface language will be automatically set to the default language pack. The default language of the Plesk distribution package (en-US) cannot be removed.