English/Italian
Knock, knock.
“Chi è”
“Dee”
“Dee Chi”
“De key don’t work open de door!”
English/Russian
Man walks by. A russian comments to his friend “on idiot” (“he’s walking”). The man overhears and launches into tirade: “An idiot? I’ll tell you who’s an idiot…”
(true story)
English/Spanish
…any number of jokes based on Spanish “embarasado” = English “pregnant”. Not sure of spelling…
What’s Japanese for handkerchief? Saca Moco
(That’s spanish for Buger Remover)
A cop is rolling by the border one day and spots a Mexican furiously rattling the burgler bars at a closed down bar. There is a big sign on the building that reads “FOR SALE, NO LEASE”
The cop asks him what he’s up to. The man replys, dice forsale, no le ase. (translation: Apply Force, It doesn’t matter)
This woman walked into a bar and asked for a double entendre… so the barman gave her one.
British English/French
Several people are eating at a Chinese restaurant, and they decide to have Peking duck. One of them points out that Peking is the old name, the city is currently written Beijing. Shouldn’t the dish be called Beijing duck? They argue about this for a while, and decide to ask the waitress, and pronounce the city the same way she does. When she comes to take their order, they ask her how to pronouce the capital of China. She looks at them like they’ve gone nuts, and says, “Taipei.”
Pity me, dear readers, this was the only joke I could remember all the way through for many years.
What does a fish do? ¡Nada! Spanish for swim. Ha.
My Spanish teacher told us this when we were learning object pronouns. I don’t remember it exactly, but I think this is close enough.
French/Spanish (and don’t even need the French, really)
A woman walks into a bar, and falls over, injuring herself. A French person who saw the accident says “C’est* la vie” (That’s life). And the Spanish person sitting next to him says, “Sí, y yo se la vi.” (Yes, and I saw her fall too.)
*I’m pretty sure that’s supposed to be the fancy French “C” – sorry it isn’t.
English/Dutch
An American is spending his holiday in the Dutch countryside where he meets a farmer with just a little knowledge of English. He still manages to get some conversation going, and at one moment he asks: and what do you do for a living?
The farmer replies in his best Dunglish: “I fok horses” *)
The American: “Pardon??”
The farmer, very happy: “Yes! Paarden!” **)
fok = Dutch for raise
Paarden = Dutch for horses
Alt+128 = Ç 
I used to know a man from the Philippines who told me that sayonara means “this is your spoon” in Tagalog (sa yo = this is yours; nara = spoon). In fact, he said, they even have a joke about that. I should have asked him what the joke was. 
In sophomore year HS Spanish class, our teacher (who was French-born and a fluent speaker of French, English and Spanish) nearly had a giggle fit over the word “con” (Spanish for “with”) one day, and one of my classmates and I were like, “WTF, mate?” (Basically.) The teacher responded that “con” means something different in French than in Spanish, but wouldn’t tell us what it meant. We prodded and prodded and prodded, but she wouldn’t say.
After class, we realized there was only one thing we could do to solve this problem.
Look it up on the Internet.
So we did. “Con” is French for “idiot”.
This resulted in many, many inside jokes in Spanish class, and a very frustrated teacher. That was a fun semester 
Uh, it apparently has another meaning too…
http://www.lotsofjokes.com/cat_21.htm
Scroll down to the French section and it’s right in the middle of the list.
:eek:
Frappe Frappe
Qui est la?
Losti
Losti qui?
Yes, that is why I am knocking.
English/Afrikaans:
What did Adam say to Eve?
Ek het jou leaf.
Ek het jou lief = I love you (lit. I have love for you)
Ek het jou (by itself) = I’ve got your…
Grim
Not a joke, rather a true anecdote…
A Thai friend of mine was asked, in her early days in Australia, “How come?”
Earnestly, she replied: “BUS!”
Spanish/English, Polish/English
My husband does this all the time. Whenever I do anything dorky, he says “You are so cool. So cool I’m gonna call you culo.”
Culo (is that how you spell it?) = ass.
Oops, I for got the Polish part.
He sometimes substitutes “kurwa”(whore) for “culo”.
Ahem. It is not the “fall” that he saw. He saw “it” when she tripped. Se la vi = I saw her it.
It seems your Spanish teacher missed the joke or you missed her explanation. It is as old as the hills.
While working in a Francophone country in Africa, a Spanish co-worker’s surname was “del Con” – which had to be changed for the classroom. "Con’ in French means ‘idiot’ but really has a perjorative meaning close to what you might expect in English.
But the best cross-language joke that I know is a pilots’ joke:
A Mexican man puts two quarters and a nickel into a vending machine but the price is 65 cents. Instead of dispensing the soda the machine it reads “DIME” so the man leans in and whispers “Pepsi”.
“dime” is spanish for “tell me”
No, “c’est” doesn’t have a cedilla. A cedilla is only for when you have a “c” with an /s/ sound in front of a, u, or o (where normally it would have a /k/ sound), as in “ça,” “acquiesçons”, or “reçu.”