The other day I noticed Addie doing the sign for milk. I don't know if that was what she was really trying to do at the time, but I'm definitely reinforcing it and she is putting it together. She has understood the sign for awhile now - I think she was 5 months old. We were at my parents' house one day and I wanted to show my mom how smart Addie was [:-)]so I did the sign for milk and she started freaking out (breathing heavily). When I didn't immediately feed her, she got really mad, so she got to eat again and we learned never to do the sign unless it was meal time! Tonight in her highchair she did it a few times so I ran to get the camera - but of course it then took a long time to actually capture it on film. You'll see that when I acknowledge what she wants she gets excited though!
We started teaching Ella sign language around 10 months old. My friend Sheree had these great DVDs (Signing Time) that we used. Now it comes on PBS Sunday mornings and they have books and all kinds of other resources available. I am definitely a fan though! By the time Ella was 15 months old she could sign over 30 words and it made communicating with her much easier. I really think it helps expand and reinforce their spoken vocabulary as well. I would recommend it to anyone!