From _en_ into a translatable _en_

On a multi language site it is desirable to translate the drupal English into the customers Englich likings.

Steps taken

  1. Goto /admin/settings/language/add
    1. Add a custom languages with language prefix en, name en-ours, english English @ Our place and native English @ Our Place
    2. Make your new language the default.
    3. Disable drupal's en
    4. Change the name en-ours into en