Routing for multilingual urls

Hi I'd like some help for setting up my routes properly for multilingual pages.

The url from my pages look like this:

Code:

controller/index
controller/method
controller/method/param1
controller/method/param1/param2 etc etc

What I'd like to do is to prepend on the url the selected language and have the ability to pass many params on my url, using a single route if possible.. So basicaly instead of using many routes, like this:

PHP Code:

$route['eng/(:any)'] = '$1/index/eng'; // controller/index/lang
$route['eng/(:any)/(:any)'] = '$1/$2/eng'; // controller/function/lang
$route['eng/(:any)/(:any)/(:any)'] = '$1/$2/$3/eng'; // controller/function/param/lang
etc etc 


which is not very efficient actually, I was wondering whether there's a way to use a single route to do this, something like this:

PHP Code:

$route['eng/(:any)/(:any)/unlimited parameters'] = '$1/$2/unlimited parameters/eng'; // which is controller/method/unlimited params/lang