“Speaking backwards” would translate in French as “parler à l’envers”. The phrase “à l’envers” has been turned, well, backwards and became many years ago “verlan”, a new way of talking. Some backwards words have since been used so frequently that they are now an integral part of the spoken French language. Speaking verlan is mostly done by young people but many words are now used by all generations. Wikipedia has a good article on verlan so check it out if you want to know more about it. The purpose of this post is to present some of the most common examples of words that are now very commonly used.
un keuf: verlan for flic (cop)
une meuf: verlan for femme (woman)
beur: verlan for arabe (generally refers to people of North African descent). Interestingly, the verlan word has itself been “verlanised” into reubeu. Note that those terms are not racist in any way.