Assign default language custom URL to translated Drupal nodes

Question

My Drupal site is in English, but supports user contributed translations. When users create a translation of the page /About, I'd like the translated version to get automatically assigned the same URL instead of being Node/123. The two versions of the page can have the same custom URL because the i18N / internationalization system appends the language code for non English pages. (i.e. /fr/About)