There are several articles relating to early intervention topics about communicating with infants at this website: http://www.educ.kent.edu/deafed. Click on the "Instructional Resources" and then "Infant/Toddler." You will find several web links to different web sites about early intervention and deaf and hard of hearing infant development.
At this website, there are articles about how important it is for parents to teach their babies some basic signs at a very young age, even young as five months, regardless of there is a disability or not. Also, it helps parents to become more perceptive of their babies' attempts in gesturing/signing. It's at http://dww.deafworldweb.org/pub/b/baby.html.
Developed by Beth Pickenpaugh, Kent State University graduate student, April 2000.