I have become progressively irritated by yelling, and being yelled at. There is yelling all over: on TV, in movies, in the street, at work, in relationships. There really is no need for it, and so I am working on not raising my voice. Ever. I'm not talking about shouting because someone is far away and can't hear you, or raising your voice to speak to a hearing impaired person. I am talking about yelling because you think you need to emphasize, or give more power to, what you are saying.
I have realized that you can say the exact same words, in a normal tone of voice, and be heard, as well, if not better, than you would have been heard if you yelled.
I have a couple of theories on why people hear you better when you're not yelling:
1. Yelling is an act of aggression, and expression of anger. In the face of anger, we all fight, or we flee. Many of us mentally flee, that is, run away without actually going anywhere. We do this by blocking out the yelling.
2. Angry people are not in control, and if you are not in control, I am going to disregard what you are saying, or, rather, I am not really going to hear you.
I'm going to do some reading on this, but I think I probably picked up these ideas from Cesar Millan. Yep, the dog guy. When we got a dog, the first thing I heard him say was "be calm and assertive." It took me ages to master this, but now I do it instinctively and more often with the dogs. Now, I'm trying the approach in the rest of my life, and surprise! Various people are hearing me now.
Try it. Next time you feel like yelling about something, figure out what you want to say, and then say the exact same thing in your normal tone, or even a nicer tone, and see what happens. For your next test, wait until someone yells at you, and repeat the above. You just may find that you end up having a rational, healthy conversation about whatever was happening, rather than a yelling match, where one, or both of you, stops hearing.