It seems more important for the parents' language to follow the child's interest and that the language be produced where the child can see it. Of course, deaf mothers begin to use more and longer signed sentences after their children show that they understand more and when the children themselves begin to produce more than one word or sign in a single phrase. Also tap on objects or point to activities to show the child what you are communicating about. Like hearing parents with hearing babies, deaf mothers repeat signs and short sentences again and again. This gives the babies several chances to notice them and recognize the language patterns.
Babies seem to find repeated language interesting.
Hearing parents can use fingerspelling occasionally with young deaf and hard of hearing children. Researchers even think that occasional short fingerspelled words might give a child a first step toward learning about letters and this can help later in learning to read. One hearing father who participated in my research told me a story about the way his deaf daughter showed her parents that it was all right to fingerspell to her. This child had a deaf teacher, who must have fingerspelled to her in her intervention program. Surely it would be too hard to understand.