For people who like languages:
However, head to medieval Basse-Ville, caught between the German- and French-speaking divisions of Fribourg, and you’ll find yourself in a no-man’s land where the two languages have become one: le Bolze.
What’s especially interesting about the language, however, is that you must have a full command of both French and Swiss German before you can begin to combine them into Bolze. Yet even those who speak both languages would not be able to follow a conversation in Bolze unless they’d actually learned the third language, which has its own unique linguistic balance and rhythm, as if precariously walking a tightrope between French and Swiss German.
There is an audio sample here:
Wikipedia has a page, but it doesn’t have much information.