You must understand one thing about the Vietnam language. We use tones to make our words. The sound you say is important, but just as important is what your voice does, if it goes up or down or stays the same or it curls around or it comes from your throat, very tight. These all change the meaning of the word, sometimes very much, and if you say one tone and I hear a certain word, there is no reason for me to think that you mean some other tone and some other word.
