I know and teach sign-language.  Just use the everyday ASL.  If you teach special signs then the child will just have to learn the 'real' signs later on.  (kind of like talking in English-  we do not teach little babies a differnt language other than English- same way with ASL.  I started talkin is sign from the day my daughter was born.  She is not deaf, neither am I.  But I was a special education teacher of the blind and deaf-blind, thus my leaning sign language.  I am partially sighted, and learned my sign language from my adult student who was deaf.  Go for it!  have fun.  Also be sure and speak the English words as you sign.  Even deaf people are taught to try to talk as they sign.   Have fun!  Diana