You’ll hope no one ever accuses you of being a “bad tongue” in France.
Why do I need to know mauvaise langue?
Whether you want to call someone out as a mauvaise langue or steer well clear of them, this expression sums up someone you’ll definitely want to keep an eye on.
What does it mean?
Mauvaise langue, roughly pronounced mo-vehz lahng (listen here), literally means ‘bad tongue’ or ‘bad language’, or ‘wrong language’.
It can be used in this sense for example – les livres sont dans la mauvaise langue (The books are in the wrong language) but you wouldn’t use it for ‘bad language’ in the sense of swearing – gros mots is the most common way to walk about swearwords, or vulgaire to talk more generally about bad language.
But its idiomatic meaning is a bit more subtle.
If the word langue is taken to mean ‘words’ and mauvais to mean ‘nasty’ or even ‘evil’, you won’t be surprised to learn a mauvaise langue is a way to describe gossips and those who say unkind or even slanderous things behind other people’s backs.
It can also be used in a more light-hearted, less accusatory way of describing someone who has badmouthed someone. In this sense, in English you could translate it as a ‘mischief-maker’ or a ‘scandalmonger’.
An old synonym langue serpentine (‘serpent tongue’) gives an even clearer idea of the slippery, slimy nature of a mauvaise langue.
It’s normally used with the verb être, like elle est mauvaise langue (‘she’s a horrible gossip’) or ils sont mauvaises langues (‘they are horrible gossips’), with an s added to the end of mauvaise in the plural.
Use it like this
Sans vouloir être mauvaise langue, je pense qu’il n’est pas à sa place. – Without wanting to sound like a gossip, I think he’s out of place here.
Les mauvaises langues disent qu’il ne fera pas l’affaire. – The gossips are saying that he won’t get the job done.
Arrête d’être aussi mauvaise langue à son sujet, tu vas le regretter. – Stop bad-mouthing him/her so much, you’re going to regret it.

