The ability to change the language is only available once logged into the system and is for the user's preference.
Once logged in, the settings tab will appear at the top, above the yellow box, if this is not appearing as expected you may have restricted access or have not logged in.
Click on the 'Settings' tab and select the language you require from the 'Language' box.
If the language you require is not on this list, you can request it by submitting a feature request at our ideas portal.
Please note that a small number of field translations are missing for some languages.