Why does my child interrupt me so often?
Small children think that the world and everything in it (including their parents) exists for their benefit. Not only that but their short-term memory isn't well developed, which means your child's impulse to say things right now before he forgets actually has a physiological basis. Therefore the very concept of interrupting makes no sense to your toddler. He can't grasp that there are other people and activities that sometimes require your attention or capture your interest. This perspective also means that whatever directs your attention away from him (a phone call, for example) is by nature threatening.
Having your child obliviously break in every time you're chatting with a friend or scheduling an appointment is exasperating, but if you keep his worldview in mind, you'll realize that he's not purposely trying to drive you insane. By the time your child is 3 or 4, he'll begin to understand what an interruption is and what the request "Please don't interrupt" means, and his short-term memory will develop enough for him to hold on to a thought (for a couple of minutes, anyway).
Can I do anything to keep my child from interrupting when I have friends visiting or I'm on the phone?
When your child is this age, your best strategies are to reduce the number of situations in which your child's likely to bust up your conversations and to divert his attention whenever he does interrupt. You can minimize your frustration by asking friends to meet you in a place where your child can play while the adults chat. A park with a sandbox is ideal -- though your backyard might work fine. If you and your partner are getting together with another couple that has a child, the perfect solution is for two of the adults to watch the kids while the other two socialize for half an hour and then switch roles for the next half hour. Also, while it might sound like an extravagance, getting a babysitter to watch your toddler while you take a coffee break with a friend can do wonders for your sanity.
As for the telephone, many parents find the easiest solution is simply to make and return calls while their children are napping or after they're in bed for the night. Another tried-and-true solution: letting your child watch TV or a favorite video, giving you a few uninterrupted moments. If you prefer not to use the TV, try redirecting your child's attention. You might want to keep a box or drawer of special toys or art supplies that get used only during phone calls, fill a sink with water and plastic cups for him to play with (as long as you can watch him), offer him a toy phone so he can talk with an imaginary pal, or invite him to participate by saying "hello." (Use this last suggestion judiciously if he's a gregarious tyke!) If your child tends to wander -- or his attention does -- putting a playpen stocked with interesting toys near the phone may be your best option.
Getting a cordless phone can also help, as it'll let you move to a quieter room yet continue to watch him through an open doorway. On a sunny day you might try taking both the phone and your child into the backyard, where he might become engaged enough to grant you a few moments of peace. If your child isn't generally squirmy or if he's in a placid mood, holding and cuddling him while you talk might work; it will reassure him that he's important to you even when your attention is focused elsewhere.
How can I lay the groundwork for teaching my child not to interrupt when he's older?
Between the ages of 2 and 4, children copy adults enthusiastically. Take advantage of this by setting a fine example for your child. If you and your partner tend to cut each other off, work on ending that habit. Also, try not to interrupt your child when he's talking to you. Any time you forget and break in on him or anyone else, stop yourself and say, "Sorry. I interrupted you. Go on." With a little luck, your child will not only absorb your good manners but your willingness to graciously admit to a mistake. You'll also make your job easier down the road if he frequently hears you use "please," "thank you," "you're welcome," and "excuse me." While he couldn't put the principle behind these civilities into words, he'll sense it -- because he'll find that it's pleasant to be around people who use them.
A fun way to introduce the concept of polite behavior is to read your child such books as The Berenstain Bears Forget Their Manners, by Stan and Jan Berenstain; Babette Cole's The Bad Good Manners Book; Aliki's Manners; or the classic (and still charming) What Do You Say, Dear? by Sesyle Joslin (with delightful illustrations by Maurice Sendak).
At times you may feel discouraged -- your toddler butts in for the fourth time while you're having a heart-to-heart with a good friend, or he refuses to say "thank you" after his aunt gives him a present. But don't give up; it's important for both you and your child that he learn the basic social graces. Participating in polite, respectful conversation is an important step toward becoming a social human being. What's more, if you don't curb his habit of interrupting, your powers of concentration will eventually become so fragmented that you can no longer finish a thought whether he interrupts or not!
The Discipline Book: How to Have a Better-Behaved Child From Birth to Age Ten. William Sears, Little Brown & Co., 1995
The Field Guide to Parenting: A Comprehensive Handbook of Great Ideas, Advice, Tips, and Solutions for Parenting Children Ages One to Five. Shelley Butler, Chandler House Press. 1999