[eluser]ShiverCube[/eluser]
What you are asking makes little sense. A language file should contain data specific to one language.
But if you must, just add an include statement in each of the language files. So for the english.php language file:
Code:
include(APPPATH.'language/shared/interface'.EXT);
$lang...
Then you only have to load the one language (as you should do anyway):
Code:
$this->lang->load('interface', 'english');