You made me think of Hispanic waitress at a breakfast in a motel in Harrisburg, PA. My wife and I and another couple were placing our order. The waitress pulled out a tissue, wiped her nose, and said "Excuse me, but I'm constipated this morning." Of course we knew what she meant, but snickered after she left. Either she caught on to our amusement, or realized on her own that she used the wrong word. She came back and said "I'm sorry, I should have said congested. We say a word like the other word in Spanish."

So, even a word with a common Latin root can trip you up.