Unable to load the requested language file: language/english/database_lang.php

I am sorry but i don t know where is the code where manage the differents files like db_lang.php and other file
But i have this error on my wamp server :

An Error Was Encountered
Unable to load the requested language file: language/english/database_lang.php

you can give me your CI code in order to don't have lots of error because i don't khow how work the MVC and i want learn