There are no prerequisite skills, and the young child is less likely to tire of this method than one in which he is constantly drilled. I had read that children with Down Syndrome are often visual learners. I had also read that the brain grows the fastest and is the most receptive to stimulation in the first few years of life. These facts motivated me to continue teaching David. I wanted to take advantage of his strengths and work with him as much as possible, at the optimum time, to help maximize his potential.
Signing helps to bridge the gap between a child's receptive and expressive language abilities.
The amount that your child understands far exceeds what he is able to communicate to you. It seems obvious that communicating is more desirable than not communicating. As a toddler, David was with a baby-sitter two days per week. When David had just turned two, the sitter said that she could communicate with David, whereas she couldn't with another non-disabled boy she cared for who was the same age. One morning, I left the list of words that David could sign with the sitter.