Helping Baby with Communication
I actually started to teach my youngest son how to sign by using very simple hand gestures for words like "want", "more", "eat", and "thank-you" when he was about 6 months of age, which is very early. He started to pick up on those words between 10 and 12 months of age. Instead of just crying or throwing something to get my attention, he was able to move his hands to indicate what his wants or needs were at that time.
I have picked up on a few of the signs from the American Sign Language, but you can basically work-out your own sign language with your child, using whatever sign you think would be easier for him or her to use. You don't have to use the exact sign that the American Sign Language recommends.
I got started with this idea because when our first son was 2-and-a-half years old, it was determined that he had a speech delay, so the speech therapist began to teach him sign language. Again, it was very simple signs for words like want, more, help and thank you. Sign language allowed him to establish communication and eventually, as he got older, he dropped those signs and replaced them with words.
When my second son was born, I decided since sign language had worked so well with my first son, I would use it with my second son also. Each child is different, so I really don't know if my second child would have spoken earlier without the sign language, but in my opinion it has really helped. His vocabulary has really expanded for being only 17 months of age.