We've been signing with DD since she was a couple of months old. She's 7 months old now. She seems to understand the signs - gets excited when I sign milk, etc - but doesn't do them back. At what age do babies normally start doing signs back? I don't remember when DS started signing back to me, I just remember that when he did start signing, he did it like crazy and was able to express himself really well. I'm looking forward to that with DD, so I'm hoping to see some signing soon!