Multi language navigation

I am working with RW since 2013, but I am new with Foundry 3!
I want to give my visitor the possibility to switch to another language in the navigation bar. I want to use flag icons of the countries and no text. As far as I see I can not use own icons in the navigation bar! Only Bootstrap or font awesome.
Or am I wrong? Has someone a solution for me?

No, sorry, the two standardized font icon libraries are the icon options that are available. You could use images of your own say above or below the navigation, but not within it.