Teach your baby the sign for the words father, dad, daddy, and papa in baby sign language with the following description and video. The sign is identical in American Sign Language for all four English words.
Father, Dad, Daddy, Papa
Form an L with the hand and tap the thumb against the forehead.
Beyer, Monica. 2006. Baby talk: A guide to using basic sign language to communicate with your baby. New York: Jeremy P. Tarcher/Penguin.