We put the shout-out on social media and we were flooded with responses.
We gathered what we thought were the best responses and the toughest words - from beginner level to extremely advanced. And a warning: Number ten is really hard.
Without further ado:
(If you can't get your mouth around the word, get it around the cake instead. Photo: Alpha/Flickr)
Fancy some custard slice? Well not if it's mille-feuille, says Facebook fan Deborah Adams Kutch. "It's physically impossible for me to pronounce correctly," she says.
"I have had more than one session with several obliging patisserie ladies trying to teach me, much to their hilarity."
(Welcome to Brouilly itself, with some vineyards in the background. Photo: JaHoVil/Flickr)
Another item that's top of the unpronounceable list is "Brouilly", a type of red wine from the area bearing the same name in the Beaujolais region. Lynn Segal on Facebook says: "I don't drink it anymore because I've been laughed at so many times! I can't figure out how to say the B at the front of the mouth and the R at the back."
(Photo: Thomas Hammoudi/Flickr)
Another answer that got people talking was "Rouen", a town in northern France. Iris Weintraub Lachaud says it's hard to pronounce "unless you're a goose".
But it's not just us foreigners who think it. Facebook follower Onürb Öhn is a Frenchman who describes himself as "nearly Rouen native" - but he says that the town's name "is still a mystery for me to pronounce... rouan, wran, roin, roan, rouen".
(Photo: Cheryl Harvey/Flickr)
Tweeter Richard Milne says that "without a doubt" the hardest French word to pronounce for him is bouilloire (which means kettle).
"It's got so many vowels/soft sounds that I sound like somebody is strangling me when I say it," he says.
Another common response was "pneu", which means tyre. Ruth Trevanion on Facebook says she "just can't get to grips with that one at all". That seems like a pun Ruth, and we salute you for it. But you're not alone. A number of people said they couldn't pronounce the word either, with one follower saying it's the "least French sounding French word" they know.
(Photo: Liz West/Flickr)
Yet another common response was "heureuse" (meaning happy). Karen Hermann laments: "It doesn't sound like a word when I say it, it sounds like I'm trying to speak through a piece of gum stuck in my airway."
(Photo: Laszlo Ilyes/Flickr)
On Facebook, Shelby Marcus Ocana says the toughest for her is the word "froid" (which means cold). And it sounds as if it's that pesky rolled r in the middle that's causing all the problems.
"My kids always crack up when I say "J'ai froid" - they say I pronounce it like "foie" [which means liver]." She then has to endure inevitable series of jokes about foie gras from the little ones, she says.
(What a frog would look like if it tried to say grenouille. Photo: Yamanaka Tamaki/Flickr)
This word, which means frog, popped up a lot. In fact, many readers sent in words ending in "ouille". Jay Fogler on Facebook says the problem with the word grenouille is the complex rolling of the r and the combination of the ou i and ll. Enough to drive you hopping mad!
Catherine Gheribi on Facebook says it's one of the simplest, yet most important words of all that she gets tangled up on.
"When I say l'eau - no one ever understands what I mean," she says.
In fact, she says that even when a waiter asks whether she would like water or wine and she responds "L'eau s'il vous plait" - they still look at her blankly.
"I want to shout 'I DIDN'T SAY DU VIN DID I? - SO IT MUST BE THE OTHER ONE'!!. She says that she's learned to order 'une carafe' now.
Photo: Susan S/Flickr
Brace yourself: The hardest French word to pronounce is the word for locksmith - "serrurerie". It was the most commonly repeated response. Blogger Polly-Vous Francais even sent us an entire blog entry about the word.
She says: "Forget it. It is not happening. It requires too many mellifluous, throaty French r's in too short a time frame (...) I find that I've barely recuperated from rolling out the first r when the next r and the next r need to come flying out of my tonsils."
With this in mind, we decided to test tourist in Paris to see if they could pronounce the word. Here's how it went: