Both my brother and my sister-in-law are deaf but my two little neices can hear. This is because my brother and his wife's deafness is not hereditary but rather the result of infant illnesses. Yet they have to use sign language to communicate with their little girls. My older neice is four and she knows the signs for most things. My other neice is 8 months old and I've observed how she uses her hands especially when my sister-in-law signs to her. Babies are very quick to learn new things. I think baby sign language is a great thing to use. Parents can adapt any signs to relate what they want their babies to learn. And in the process this strengthens the bond between parents and babies.