At each stage of childhood, the child is learning to be an adult and to develop as an independent, free thinking person. However we all to often forget this and instead try to form brain washed clones. I admit (not so proudly) that there are times that I fall back to these traps of conventional parenting. We say "old habits die hard" or "well that is the way my parents did it" to justify our actions, but we know in our hearts that is no excuse or we wouldn't feel the need to justify. However the results speak the truth. We are either left with aggressive rebellious children or the fore mentioned clones. The clones do well in our society because they do not think on their own and most of the rest of society is comprised of clones. If you need evidence of this just drive through the suburbs where every house looks the same. The rebellious can be okay but normally have a hard time in life because few like someone that is not co-operative at all.
If we can't yell, how do we correct?
Our children are bound to see what they are allowed and not allowed to do. First, you must teach the child what no means. How many times have you heard a parent say "What part of no don't you understand?" or even felt the desire to say this. We fault the child for not listening, but perhaps the question being asked is the key to the problem. What is the part of no that the child does not understand? Is the child aware that no means "you can not do that" or have you like many parents taught them that it means something else. In my household growing up "no" meant, you can't do that until you annoy me enough and I either threaten to beat your butt or give in and say "do what you want to do you're going to anyway". Who the child is interacting with can even change their understanding. How many times have you heard a stressed out mother exclaim "I just don't get it! I yell until I am blue in the face, then their father comes home, says "No!" in a clear calm tone and they listen." In this case, it is often because Dad has set a clearer no nonsense demonstration of the word no and the consequences of not listening or pestering. Yet again we see that the yelling is not the effective mode, but giving the child a clear understanding.
I myself reached a point where I felt I was constantly yelling at a child to stop and....(fill in the blank). I found myself very stressed and with nothing accomplished for it. I decided enough was enough. I do not wish to live in a combatant home, but I do not wish for unruly children either. I had to find something so that I could have the home I wanted. I decided to try emulating a sect of characters from a book series I love called the Aes Sedei. They maintain outward calmness no matter how they are feeling at the time and never shout. Instead when others begin to shout they whisper so that the shouting person must strain to hear them. Low and behold, my children began to simmer. I was feeling more piece than I had in a while and my children seemed less agitated as well. We are still in the beginning stages of this return to a calm effort, but I already see a shift for the better in both my children. When they do something rude or unacceptable I simply tell them that it is so and how they should behave. I give them the choice of stopping the action and making the correct one or sitting in the corner until they are ready to act in a civilized manner. There is not altercation, there is no room for argument, the child has two choices and I give them time to consider it. They are normally frozen in place after given the choice. Sometimes they elect to sit in the corner, but more times they say they are ready to stop the action and be civil.
Now let me add the disclaimer that should the child be in harms way and yelling is the only way that you can think to get the attention fast such as, "No! Don't run into the street" or "No! That is hot don't touch it!" should arise, I believe it does not harm to yell, though you most likely will startle the child and may even expect it to cause tears. At this point it is important to go to the child and tell them why you yelled. How you were scared that s/he would have gotten hurt and needed the child to stop quickly. If your child is not yelled at daily, yelling in these cases will even be more effective at getting a quick stop, than if that tone is a normal one. Thus my final argument against yelling as a general rule. Eventually, as the cliche states, "it goes in one ear and out the other". In effect, the child will learn to tone you out and not listen at all. For if you do not respect the child, the child will eventually stop respecting you.