Desperate help required with menus

Hello,

This is my first post on the WordPress forum but I’m desperate need of some help.

I’m working for a client on a WordPress blog which uses the Theme1787 (http://freelancewp.com/wordpress-theme/theme1787/) theme. The website in question is an Swedish language sports website, and I’m copying and translating each page into English (but the Swedish ones will remain).

They have asked if once a user clicks on the ‘English’ tab can the whole site shift over to the English pages and use a new English menu (basically a mirror of the Swedish site, but in English).

Is their any way to run 2 different primary menus which only appear on the language specific pages?

Any help would be incredibly welcome.