Most moms are yelling to her children to call them. Actually you dont have to do such a thing. You have another choice for that.
Try to use whistle to call them. Here is the story of Lynn, mom of 2 who has succeeded in using whistles.
Because I cannot yell very loud and my children have common names used by many other families, I have developed a special whistle
that lets them know that I need to know where they are.
When I walk into daycare, all I have to do is whistle and they both turn their heads
and smile. Once, in a store with my mother, I had my son and she had my daughter, I was ready to go and couldn't find them. I whistled
and my daughter told my mom "I have to go, my mommy's looking for me." My mother hadn't heard anything but little Katie heard me.
We have used this technique since the kids were very young and it has been a great safety technique for my family.
What do you think? You can try it at home.