Mispronunciations are often physical
It started with "be-nember." This was my son Henry's word for "remember" when he was 2. By 3½, he was also saying "be-tend," "be-stroy," "be-scape," "be-splore," and "be-scuse me." Since r sounds are harder to make than b's, Henry shifted into the pronunciation that was easier for him. Then he fell into using this form for random other words that started with d, p, es, and ex as well, before eventually outgrowing the habit.
Children often learn new words before they have the motor dexterity to say them. That's why "elephant," for example, often gets truncated to "ef-ant," which are easier sounds for the mouth to make. In San Rafael, California, Mary VanClay's son, Andrew, 3½, likes his vitamins -- or as he calls them, "vitawimps."
Your role: Have patience -- and keep a notebook handy, if you're so inclined. How else would I have remembered "wangy-tangys" (orangutans), "squish-squash" (washcloth), "la goat" (yogurt), and "destructions" (instructions)? Not only is this a mighty cute phase, but some tongue twisters might become household favorites.
They have sponges for ears
"How are you today, class?" Ryan Minniear's teacher asked her 18- to 36-month-old charges at daycare in Mason, Ohio. "Water in the pool!" Ryan replied cheerfully. "It wasn't long before the whole class was saying it, too," says mom Laura. "After days of trying to interpret, we figured it must be what he heard when someone said, 'Wonderful!'"
Blame kids' explosive vocabulary growth, especially around ages 3 and 4. Try to learn a language as an adult, and you'll find it takes many exposures before you can call up a new word and use it comfortably in your speech. Not so with preschoolers. You only need to label an object once and they've absorbed it. What's more, they can use it correctly later. "Grandma will protect you," Diane Paul told her grandson, Gabriel. Later in the day, he told his dad, "Ma-mom will protect me from monsters."
Of course, your child won't always hear the new word exactly the right way, and sometimes the source doesn't enunciate well. "It's like the game of telephone, where the words change with each new listener," says Paul. One evening my kids were having Chef Boyardee for dinner. "Uh-oh, geh-geh-o," said Margaret, then 15 months. "Did you hear that? She heard us say, 'Uh-oh, pisghettios!'" exclaimed Eleanor, 3½. Sometimes kids pick up the sounds without the context, leading to funny mistakes -- as we've all heard the alphabet song sung: "H, I, J, K, ella-mennow P."
Your role: Know that occasional misses are to be expected. If misunderstandings are frequent, or your child only echoes everything that is said to him, however, have him checked out by a speech-language pathologist. These can be signs of a problem.