Retaining information

It is crazy to think how much information Faith retains when I teach her. The other day I noticed that she had picked up her sign language again. She hasn't used it since she started talking a few months ago. So I thought she just spit one out randomly until I decided to actually ask her to use her hands to say words to me. As I strapped her into her carseat yesterday I asked her to say all the words that I remember teaching her. After she spoke them she used her hands to repeat each one correctly. At one point in time I thought that it was such a waste to teach her signs after she stopped using them. However now that I know that she actually retained that information I will continue to teach her new words. However, I myself need to learn them first.