We found that Macayla could use some signs to help communicate for a short time. She learned a version of the sign for "more" and that was helpful, especially when she wanted to play in the water. She would often sign "more" to let us know she did not wish to stop.
One helpful resource is ASLPro.com. It is free to use their website and they provide video demonstrations of the signs. They do accept donations to help keep this wonderful resource going.