They simply communicate that you are listening. Other healthy communications include monitoring your tone of voice and body movements. Your nonverbal communication is as important, maybe more so, than your verbal communication. Consider what it was like growing up in your home. You might have agreed with what they said to keep from suffering the consequences, but it was their body language that told all.
Timing is important as well.
Look for moments when you and the child are in a comfortable and safe space, physically and emotionally, before listening and speaking. When dinner is over, I will set down and talk with you. Of course, you need to be able to talk after dinner or trust will be destroyed. It isn't a good idea to talk to your child when he is tired, hungry, or upset. Wait until the right moment to communicate.