Spoken French is full of hundreds of tiny sounds and inflections that carry a whole lot of meaning. One phenomenon is to do with some French women and their peculiar way of saying "oui".
Halfway through a conversation with a French woman, you might hear her suddenly inhale sharply, and think she's gasping in shock.
It might sound like "whhhoui" or "wheeee" (we have no idea how to spell it).
No, she's not aghast at your comment that French cheese smells too strong, it's just the strange way that many French women (and far fewer French men) say "oui", which of course means "yes".
Basically, the word is said on the inhale rather than the exhale.
These short whistling gasps sometimes punctuate interactions like conversational hiccups.
If you still don't know what we're talking about then watch the video below.
Perhaps you've never noticed it. Some French women who do it don't even notice.
Many have no idea why they inhale "oui".
"I do it, but I have no idea why though," language expert Camille Chevalier-Karfis from the site French Today tells The Local.
Is there a real reason for the breathed-in "oui"? It's a question bloggers in France have struggled to answer in the past.
"I don't understand it and they ALL do it, even on TV. What is with that?” wrote "Emilie in Paris".
Luckily, there's a whole field of study on noises we make on the in breath.
"Although it is used in slightly different ways in different countries, there seem to be some common reasons in most places," world expert on the subject, Robert Eklund, told The Local.
"Basically it's ‘paralinguistic,'" Eklund said, that means "it doesn't signal any meaning, but rather signals attitude".
In Sweden, an inhaled "ja", "yes" can be used to change or close a conversation topic, but in Norway, it shows annoyance says Eklund.
So what attitude is a French woman showing?
Well, saying "oui" on the inhale can mean many things but likely depends on the person.
Some French women told The Local they use it when surprised, stressed, reacting automatically, or even when they're cold .
Academics studying the subject of inhaled words found that French women often inhale when saying "oui" to show a doubtful or complaisant yes.
Another researcher suggests that the inhaled "oui" among French women shows reluctance or caution.
So if a French woman or man responds in this way, perhaps they are not totally convinced by what you are saying.
How can I breath in "oui" too?
If you really want to disguise yourself as a French woman, the next time a French person is talking about something you're not sure you agree with, like "UHT tastes just the same as fresh milk", or "French drivers are the best in the world", start clearing some space in your lungs ready to breathe in quickly.
The "oui" needs to be short and sharp intake of breath, like you've accidentally touched a hot stove (just don't use any expletives).
Although bear in mind you might want to use it with caution, because it appears it can get on the nerves of some locals.
"I laugh at people who do it," one young Frenchman told The Local.
Hit French YouTuber "Norman" even included the inhaled "oui" in his top 13 "worst" French expressions (jump to 1 minute 13 seconds).
According to him the inhaled "oui" is "ugly". He says it makes you sound like a "secretary" or a "Madame Pipi" – a popular French term for (female) toilet attendants.
But he helpfully points out that it just doesn't work for other words in French. So don't start inhaling you "non" or your "bonjour".
What do you think? Have you heard any French women doing this? Or do you do it yourself?
By Rose Trigg