So I have been signing with my daughter since a couple months old. Before her illness that I believe led to the diagnosis, she was signing a lot back. We started using the Signing Time series with her at about a year and she is addicted! We ended up buying the first three after extensively using the library copies. I finally got our library cards and reserved three more and upon getting in the car with them she stole them from me and refused to let go for an hour. I had to pry one from her to put it on! I am in love with this series. It is so easy to use and kids love them! I am even refreshing my signs. And my mom, who I have been trying to teach sign to since I was 3, is picking it up! I can not praise this stuff enough. My daughter is finally trying to sign back to us again and I love it! Next step is saying "I love you Mom" verbally or sign, doesn't matter!
We have been using sign since my daughter was 2. The teacher discourages it now because Emily is a little more verbal, but it really helps in public to let other people know that there is an "issue" with the child. My son also signs and we do a refresher course online every few months just to give us some new signs to use. I have not seen the signing times- we will look into that as well. thanks and best wishes. HUGS !!