We learned the signs for happy birthday, jump, walk, run, train, bike, plane, family, class, dog, cat, fish, horse, rainbow, clouds, rain, outside. We learned how to count in sign language (which is a TAD bit different than normal counting with fingers). We can say our ABC's and sing certain songs in sign language.
The best time to start teaching them is when they're little. They pick it up SO QUICK. And I know you're probably thinking "When are they ever going to need this. When will I even need this?" You might.
When I worked in the nursery at the Y we had to know enough sign language to tell a mom that her son needed to come in with shoes the next time she brought him. And one of my best girlfriend's sons had learned sign language and would use it when he needed to ask to help or when he had to tell us that he needed to use the potty.
When Alanna was in kindergarten her teacher taught them how to say "thank you" in sign language. The cashier in the cafeteria was deaf. In the 10 years that she had been working there, not once had she had a conversation with anyone who bought lunch from her. After Mrs. Haney taught her class how to say thank you, that day at lunch when the kids went through the line they all signed "thank you" to the cashier. It absolutely made her day.
On top of all that, it's so much fun to learn! For the parents AND the kids.
Check out the videos on YouTube.com or at SigningTime.com
* As an afterthought. How many parents have been frustrated because you don't know what your child is trying to tell you. How many of you have had a child who gets frustrated because they know what they're trying to say, but don't know how to tell you. Teach them sign language. If they can't find the words for what they want to say.... or maybe they're too little still for actual words that make sense to anyone but themselves... they can sign it. It eliminates the frustration and crying and makes life easier for BOTH of you. :-)