Yelling for motivation vs yelling to teach vs yelling to demean. 3 different animals and all have pitfalls and shouldn't be ignored. Normally you do more damage than good especially if you are using it as a teaching tool. It normally crosses a line to demean the child and the damage can be irreversible without professional counseling. It is for this very reason I believe coaches need to find another method to teach or discipline the kids----------especially girls regardless of age.
Look, none of those kids purposely do something wrong while playing softball. They need to be understood and taught. Kids don't learn at the same pace. Some kids simply don't rank the game as high on their list as others (coaches). Girls don't normally "live" the game like boys. All things need to be considered before blowing a cork! The favorite saying "I treat all the girls on my team like they are my own" may or may not be one of your brightest moments as a coach! There are many factors to consider, especially if a player is having a problem that is chronic. Communication from coach to player may need tweaked. Many girls shake their heads "yes" even when they don't understand what you are saying. they don't want to appear stupid so they simply agree. The coach is the one needing to change. Talk to her in a way she'll understand. Some girls may be having an equipment malfunction. Again, it's up to the staff to notice the problem and address it. Lastly, some kids simply cannot function physically as well as you want them to. They don't have the athletic ability. It's the coach that needs to accept this and work to help them improve if even possible. Yelling at a kid and demeaning her for being a slow runner will not help. Get her with somebody that can help her learn a better running technique is the answer.
One last thought, when teaching girls you need to remember that many will not remember. They don't think ahead or are mentally into the game like yourself. I always tell coaches "don't yell at a girl if she does something wrong unless you are sure you told her ahead of time what you wanted her to do." In other words, the classic "you should know better" is nothing more than admitting you didn't do everything you could at the moment. Age is not an issue as time doesn't always become a teaching aid.
Save the yelling for shouts of joy and use your head and work with all the other moments as teaching moments and times of reflection.