My mum and step-dad recently went to Austria.
My mum had learnt a few phrases and decided it was time to start using them. She was in a shop and was determined to say “Danke Schon, Auf Wiedersehen”
She gets to the counter, pays for her stuff and before leaving says…
“Dankoo… Bye!”
On one of my travel nurse assignments, the resident assigned to the ICU was from Chili. She was strikingly beautiful, so the interns (all male) tried their level best to impress her. One poor young thing had been studying Spanish to impress her.
His patient was also spanish speaking, but she had little or no English. She’d been unable to eat for several days, so when she could eat, the intern decided to give her some choices… in Spanish… in front of the resident.
I was just outside the room when the resident raced into the hallway busting a gut. I asked her what was so very funny. It seems the young man got just a tad confused.
He wanted to offer the patient a lobster tail. Unfortunately, he had aquired some of his Spanish on the streets of Tijuana. He asked the 70 year old woman if she’d like a lobster cunt for dinner.
He didn’t try to impress the lovely resident again.
He he he, both the previous posts are very funny.
The legendary one in my family is my father’s holiday job as a guide in an aquarium.
One day a group of French speaking Belgian tourists came into the aquarium. He knew a little bit of French but unfortunately didn’t know the word for “fish”. However, he did know that “pecheur” (I hope I have it right now) meant “fisherman”, so he cleverly deduced that “peche” must be the French word for “fish”. So my poor dad proceeds to with the whole tour (the natural habitat of this peche, the colours of that peche and so on) on that basis and can’t work out by the Belgians are falling about the place laughing. They didn’t tip at all, which I still think is rather mean considering it must have been quite entertaining.
(Peche=peach in French)
One of my friends here in Panama once told a busload of people he had to get off because he had an erection.
When on a bus, it’s customary to shout out Parada! (bus stop, bus “stand”) when your stop is approaching.
Instead of just saying parada, he yelled out “Tengo parada!” Since penga parada means “erect (standing) penis,” this would translate as “I have a stiffie!”
Everybody made way to let him off as quickly as possible. 
I remember the look of horror on the face of a neightbour of mine when I tried talking to him in French. I think he was from the Ivory Coast.
Anyway, I thought I was doing quite well and we were chatting away quite nicely and to my delight I could understand what he was saying.
Then
His eyes widened and he backed away, looking at me most strangely.
It was only later that I realised that I had mixed up the French and Spanish words for the verb to drink (boire and beber respectively, as most of you polyglots will know)
I thought I was telling him I was off into town to meet some frind for the evening and that we would go and have something to eat and a few drinks.
I’m assuming that my bizarro attempts at pronouncing a Spanish word with a French accent were tragic enough, without the realisation that the Anglo-Hiberno-Franco twist I put on beber made it sound like bebe.
I’m sure he thought I was off into town to meet my friends and eat a baby.
In Spanish II, I asked the woman that came to talk to us how many sphincters she has instead of asking how old she was.
I still do it occasionally, only this time it’s intentional.
One evil thing about basic French dictionaries is that they don’t include dirty words. Not so you can use them, but so you can avoid them. The biggest problem is that they all say that the verb baiser means “to kiss.” It did about 300 years ago; now it means only “to fuck” (although “un baiser” is still a kiss; a fuck is “une baise.” To kiss is embrasser.)
Every English-speaking learner of French makes that mistake… one time. Fortunately I did with a French exchange student around my age as opposed to, say, a sweet little old lady.
In german class we were learning the parts of a car. Headlight in german is “Scheinewerfer.” Literally, Light-thrower. This was fine until one student pronounced it “Schweinwerfer,” or pig-thrower.
James Bond never had one of those on his Astin-Martin.
When I was an exchange student in Germany, I learned most of my german by ear. Of course this meant that sometimes I misheard or misunderstood what exactly the word was, but I could fake it generally by making a similar sound. One day, I came home from school and told my host mother that I had a terrible “baumschmerzen.” She did a double-take and started laughing her ass off. Apparently what I meant to say was bauchschmerzen- a stomach ache. Instead, I told her I had a tree-ache. THAT took a while to sort out!
You are a tease, to stop the story at that point! 
The relevant word from picunurse’s story is concha, which in Spain and most of Latin America means “cone, shell, conch” like the English cognate – but in the Coño Sur (Uruguay, Chile, and Argentina) references a quite different object which also has a rounded coral-pink surface with a rippled slit down the middle.
I studied German all through High School, then switched to Spanish in College.
I will never forget the look of consternation on my Spanish Professor’s face when, one sleepy Monday morning, I answered one of his questions half in German, half in Spanish!
I took several years of French in high school. Enough that I can still track conversations pretty well, but as far as joining in, eh, not very good at all. When I got to college, I figured I’d start with a clean slate and studied Chinese, which I got fairly good at.
Several years back, I had just returned from a trip from Southeast China, and on my way home, I stopped in Paris to see a Tom Waits concert. I met up with a friend, entered the theater, looked at my ticket, and couldn’t figure out where the hell I was supposed to sit. So I found an usher, gave him the ticket.
The usher just stared at me as though I just put a dead fish in his hand. So I thought for a moment, tried to gather my French-speaking skills, and very calmly asked him, “这个位子在哪里?”
He blinked. Several times. And then pointed in the general direction of my seat.
Donde estan mis zapatos fritos?
(bolding mine)
That has to be a Freudian slip.
Is that the country between Texas and Mexico?
My little bro (native Spanish speaker) commenting on my mom’s pregnancy to the English teacher: “she’s embarrassed” (embarazada = pregnant in Spanish).
When I was in Hong Kong I was looking for ant repellent. I knew that mosquito repellent was “mun pa soi” (literally “mosquito fear water”), and I knew that Cantonese for ant is “ngai”. So I went into a shop and asked for “ngai pa soi”.
The shop assistant nearly fell over laughing. It’s all about context, see. I had actually said “Hello, I would like to buy an ant that is frightened of water”.
Not so much a boo boo, but cross-language borders
Sitting at the cousins house in Germany, everyone was drinking beer, save for me.
My husbands cousin, our superlative hostess, digs around for a bottle of wine to open for me.
She comes out of the kitchen brushing off the dust off the bottle with a laugh.
I make a comment, " Oh, that must be the **gift ** wine."
Everyone chuckled.
Gift (not certian if it is the same spelling) in German translates to ‘poison’.
The double entendre of " giving a houseguest poison wine" and ‘here is a bottle that was given to us as a gift and therefore not decent enough to drink’ was a merry good chuckle.
My Spanish isn’t great. ( as testified by my spelling of Chile ) but, did you just ask where to fry your shoes are?
Once in high school, with one of our french teachers, one of the guys was acting up, as usual. He wouldnt’ sit down or something, I can’t remember. Anyways, the teacher asked him if he would like to sit over ‘here’, ‘here’ being next to her desk at the front of the room.
Now, at this point the response he wanted to give was “No, I’m not completely insane.” However, he couldn’t remember the french word for insane (fou) so instead he used a tactic that we all used from time to time when we couldn’t remember a word (and often, it worked). He bastardised the english word.
Now, you’ve probably figured out that ‘insane’ doesn’t sound at all like ‘fou’, even with a bad french accent. However, it does sound somewhat like another french word, enceint.
The response he gave the teacher was “No, I’m not competely pregnant.”
(This guy also, the year before for an improv in English class, gave birth while stuck in an elevator)
My college French instructor told us that on one of his trips to France he accidentally asked his host if he could put his mistress on the floor when he was trying to ask if he could put his mattress on the floor.