Different Primary Menu for different pages

All I want to do is have a different primary menu for certain pages.

One page is in English and another in Spanish, and French etc. I don’t want to use one of those dodgy translation plugins (we are a language centre, so it must be 100% correct). We have all the translations we need, but each set of languages will need different primary menu.

This is the only issue. Everything else is shaping up just fine. So all I need to do is have specific primary menus for specific pages.

If not possible, I guess the next best thing is to have different sites for different languages.