You can set both default system language and admin interface language.
Default language is the language of newly created accounts, including navigation menu, form and control labels, context help, and system messages. However, every user can override the default language with one of those available in the user control panel.
Currently Parallels H-Sphere comes with the following languages: English, Russian, Italian, French, Spanish, Dutch, German and Portuguese. You can also add new languages by installing language packages from http://download.hsphere.parallels.com/downloads/index.html#languages, compiling new language bundles, or bulding new language packages. See Customization Guide for the info.
Default language affects the default regional settings. You can set custom currency or currency pattern, but mind that they will be lost once you change to another language.
To change the default language:
Unlike the language described above, which by default is set in all resellers' and users' cp, the language configured from Admin User menu relates only to your admin control panel, including reseller and user accounts which you access from it.
To change admin interface language:
Important: Now, when you visit accounts of your resellers and end users from your cp browser, they will appear for you in the language you just set. However, original language chosen by owners of these accounts will remain unchanged.