We purchased your book 6.5 months ago when our daughter was 6 months. We have been using the same few signs with her for most of that time but have introduced a few more signs to her in the past month. She is now 12.5 months old and a couple of weeks ago she started to sign back to us with the "sleep" sign. I only thought she was using it for the Teddy Bear Says Goodnight book that we use for her. Then just a few days ago she started to sign the "teddy bear" sign when she sees pictures of teddies in books. It was so amazing! I was feeling so discouraged that nothing was happening for months but as very pleased that i percerviered with the signing and hope that the understands the other ones that I have been using with her. Thank you and hope that others are also encouraged to keep on signing to their children also.