CakePHP translate behavior : using alias for locale

CakePHP translate behavior : using alias for locale

how can use aliases for locales in i18n cakePHP i used,
Configure::write('Config.languages',array('eng'=>'English','fra'=>'France'))
;
but it will save Englis as locale in i18n table and only 6 chars for
locale. I don't want change the locale with aliases. locale been in
standard (eng) in table but in show time print English as alias. It will
be useful when print language title on calling loops or making badges. i
can override the i18n table and change the max chars of locale field, but
is there any standard or general solution?