All children need to learn to respect others. One way they can show lots of respect is by not interrupting when others are talking. I have an easy - yes easy! - and practical way to teach children how to avoid interrupting taught to me years ago by a preschool teacher.
Step 1: Explain to your child why interrupting is so disrespectful. It's best to do this when you're both rested and in a good mood - and before your child starts interrupting. Cuddle, look your child in the eye, and use a friendly tone of voice. Explain that interrupting is just like saying "Nobody else matters. I'm the only person who matters right now."

Step 2: Explain the Interrupting Rule. When your child wants to speak to you, but you are speaking to someone else, they should say nothing, but put their hand on your shoulder or, if they can't reach your shoulder, you arm. You will then place your hand over your child's as a silent way of saying, "I know you want to speak to me. Give me just a moment, please." Maintain this position; then, within in a minute or two, stop and ask your child, "Thank you for waiting, honey. What do you need?"

Step 3: Explain that if you're having an important phone conversation, one that can't be interrupted, you will warn your child before you get on the phone. In such cases, your child will have to wait until you are off the phone to speak to you - unless there is a true emergency. (Be sure to define this, because usually a child's idea of an emergency is different from an adult's. I tell my children that if someone is dying, bleeding a lot, or gets burned, that is an emergency.)

A few other tips:

* Set a good example. If you interrupt others, your children will notice and conclude that interrupting is no big deal.

* Once your kids know that interrupting is disrespectful, they will tell everyone - adults and kids - this new-found information, often in a way that others will find rude. Teach your children never to yell "I was talking first!", but to instead politely and calmly overlook the interruption. With siblings, this will be harder to accomplish, so you may need to teach your children to quietly and politely say, "I'm sorry, but I was speaking first. May I finish?"

* Don't neglect to memorize some Bible verses about the importance of respect. For example:

"Do to others as you would have them do to you." Luke 6:31

"Children, obey your parents in the Lord, for this is right. ^'Honor your father and mother' (this is the first commandment with a promise), ^'that it may go well with you and that you may live long in the land.'” Ephesians 6:1-3

 "Do nothing from selfish ambition or conceit, but in humility count others more significant than yourselves." Philippians 2:3

"Love one another with brotherly affection. Outdo one another in showing honor." Romans 12:10