More parents are teaching their little ones a short vocabulary of American Sign Language, saying the youngsters can pick it up more quickly than speech. Toddlers are able to grasp sign language quickly because they usually have motor control of hands and fingers much earlier than the muscle groups required for talking. Experts say signing can help with language development later. "The more you interact with your children, the better their language skills are going to be," said Kathy Hirsh-Pasek, a professor of psychology at Temple and an expert in language development.