Mama is often one of the first words that a baby will learn to speak. Until your baby can stalk, however, you can teach your baby the sign for the words mother, mom, mommy, and mama in baby sign language with the following description and video. The sign is identical in American Sign Language for all four English words.
Mother, Mom, Mommy, Mama
Form an L with the hand. Tap the thumb against the chin.
Beyer, Monica. 2006. Baby talk: A guide to using basic sign language to communicate with your baby. New York: Jeremy P. Tarcher/Penguin.