Sometimes a parent starts yelling simply because the children are really out of control. So the parent thinks the problem is their desire to yell, not realizing that the way the children are behaving would make ANY human being yell and scream!
If that is the case, and it may not be, we would recommend you get ahold of some child-training/parenting materials and start looking into making some changes in your home.
When children have to be begged, wheedled, manipulated, or dragged into obedience, it makes life VERY frustrating on the parent, but is also very detrimental to the child.
A healthy home should have lots of loud laughter and special snuggles and wild wrestlings and happy work times...but it should also have children who have been trained to obey. When the children have been properly taught to obey (which involves training them to do so, not disciplining them into it), it makes angry parental outbursts very rare.
I only mention this because I have a friend who is always praying for God to 'heal' her of her screaming and yelling habit. But the problem isn't her screaming--I get around her children for 5 minutes and I want to scream too!
The problem is her children are so rebellious it would make anyone scream. And they have never taught them to obey (probably because they had no idea how to, or that they ought to).
The children get asked to do something about 50 times before they will do it, and so they know (well, actually, they've been TRAINED by their parents) that they don't have to do what Mom says...
until she reaches that super high pitch and starts frothing at the mouth.
They know Mom won't actually enforce her word until she gets to that point, so they push her to that point every time...
It's not
their fault--that's what they've been trained to do (it's very similar to training a puppy--for example, you let him jump on you when he's mid-size, then he'll always jump on you...so don't yell at him when he's an adult and jumping all over you, because YOU trained him to think that was ok!)...
In this case, Mom's not exactly obedient either though, which doesn't help matters much--she's in rebellion toward Dad, and nobody seems to know much about obedience one way or another...unless, of course, it's something that they WANT to do...
Anyways, all that to say that sometimes the problem isn't the yelling--but if it IS something deeper, then allowing God to work on that area will be something that will help not only your problem with yelling, but many more areas as well! Yay!
Lots of Love in HIM,
Mol