I've been similarly "burned". I was impressed with an anti-drunk driving poster I saw while on a trip to SHAPE in Belgium. I didn't have a French dictionary handy, so I grabbed a French/English dictionary at the convenience store next to the cafeteria and tossed it in my backpack. Later that evening, I pulled the dictionary out at my hotel room to attempt a translation. The word I didn't understand was translated as "bloke". Oh crap, the dictionary is UK English, not American English.
I have foreign-language dictionaries which take the pronounciation of southern England as standard so tell the foreigners using the dictionary that an "r" at the end of a word is silent.