Change Drupal interface language back to English I made the mistake to translate the Drupal interface in my local language. But since the language is set into the database, I can't delete this language using the Drupal UI. And I'm not sure which file(s) to delete in the database.  

Does anyone know a (faultlessly) way to translate the Drupal interface back to English?
You can change the language back to English by adding this to the url of any page:

&amp;language=en


EDIT:

To have a seperate admin and front end language I'd suggest looking at the Admin Language module - http://drupal.org/project/admin_language

SECOND EDIT:

To do this via role have a look at this page - http://deglos.com/blog/2010/06/12/overriding-language-drupal-backend

They are doing what you want with a custom module. You could throw in the user role code there using the global $user.