In a Brazilian cafe, a woman sitting at a table next to mine sneezed, and I said, "Saudade" (word for longing, "saudade de voce" means "I miss you"), instead of "saude" (to your health)
The British pronunciation of tomato (toe-mah-toe) is very close to a vulgar expression in Chinese;
Chevrolet Nova was a car made in the 1960s. In Spanish, "No va" means "No go," so the ad campaign in Latin America was a failure;
The English word "brand" in Thai is close to the American cowboy exclamation "yeehaw!":
Although the written word for "end" in Swedish is "slut," it is pronounced nothing like the English word "slut". It rhymes with "flute".