The reality is that Paris and its "difficult" banlieues [impoverished suburbs] are two worlds that are completely foreign to each other. They don't even speak the same language: polished, accent-free French on one side, the verlan, or "reversed" speech, of the housing projects on the other.

I was intrigued by the notion of verlan and decided to look it up.

Verlan is a form of French slang that consists of playing around with syllables, kind of along the same lines as pig Latin. Unlike pig Latin, however, verlan is actively spoken in France - many verlan words have become so commonplace that they are used in everyday French.

Verlan was invented as a secret language, a way for people (notably youths, drug users, and criminals) to communicate freely in front of authority figures (parents, police). Because much of verlan has become incorporated into French, verlan continues to evolve - sometimes words are "re-verlaned."

About verlan, [2], Wikipedia adds:

Generally speaking, creating a verlan word on the fly from any random French word will result in smirks.

A brief clip from NPR's On Point about verlan is available.

Fascinating.

The French Disconnection