How do you get PointFire 2013's  language toggle to work smoothly with Friendly URLs?  That is to say, if you have a friendly URL with a term in language A for a page and you switch to language B, how do you ensure that it switches to the friendly URL of that page and not the full URL, and that the entries in the navigation menu are in the right language?

Say that on your publishing site you have a page in English and a corresponding page in French.

First, to have friendly URLs at all, you have to turn on Managed Navigation and define a Managed Metadata term set.  If it's not already on, go to Site Settings > Navigation page and select the Managed Navigation options.  On the same page, select or create a navigation term set.

For this technique to work it is not necessary that the term set be multilingual, in fact SharePoint's managed navigation does not respect the localization of term stores.

Now go the navigation term set in the Term Store Management Tool and select or create the English term within the navigation term set that you want to use as a friendly URL.  In the "Navigation" tab, check off "Show in Global Navigation Menu" and/or "Show in Current Navigation Menu", and select "Term-Driven Page with Friendy URL".  In the "term-driven pages" tab, check "Change target page for this term", the click on the "Browse..." button and select the English page.

Now select or create the French term within the navigation term set .  In the "Navigation" tab, uncheck "Show in Global Navigation Menu" and/or "Show in Current Navigation Menu" to make this term invisible, and select "Term-Driven Page with Friendy URL".  In the "term-driven pages" tab, check "Change target page for this term", the click on the "Browse..." button and select the French page.

Go to the page Library where these pages are set, display them as a list, normally by selecting "View All Pages" in the page ribbon, and link the two pages together using the Manage Variations menu item.

Now go to the Multilingual Translations list and add the english term and its french translation.