It’s not what you say, but how you say it. Do you familiar with this statement? I do not agree with this phrase for sure, because I am thinking words that you say are also very important in conversation. This isn’t news for anybody that people are using language for communication. When people are speaking they are using many ways to express all what they are going to say. Ton of voice, body language, gestures and facial expressions may help them with it. Some people speak very fast and loud, someone slow and guilt, but anyway, all of them try to communicate and wish to be understood. I am absolutely sure that rapid speech doesn’t always promote 100% of understanding. You may not pay attention to all information what you get because of rapid speech. It’s my point of view maybe because English isn’t my native language. If you want to express the main idea for some words or sentences you should put the stress or raise your voice on it. When you say some phrase, all of the meaning of it will be depend from stresses which you put on it. But, like I said before, emotions also help or sometimes interfere on communication.