Which language to use?

Facebook seems to be confused. These are the notifications it sent me when two of my friends clicked "like" on one of my links (which is, by the way, a hilarious scene of a few people with phobias at a phobic reunion)


As you can see, in one of the notifications it says "lien" instead of "link", which is simply the French word...which probably means that Pauline's using Facebook in French. It's the first time I've seen this bug though...does this mean that most of my friends (even the French) are using Facebook in English? :P

(I was going to post this yesterday, but with all those music videos it kinda slipped my mind after I had saved the screenshot)