Research shows that hearing children can raise IQ 8 to 13 points by doing sign language.
Signing with Preschool Children: Using signs with preschoolers and kindergartners aids in language and literacy development and helps retrain information better.Signing with Preschool Children
How ASL Improves Language Development: Children who learn sign language use both sides of the brain which causes building of connections in the brain. Children who are taught sign language has demonstrated better spelling and larger vocabularies than children who did not learn sign language. They also have a tendency to show better speech and communication skills. How ASL Improves Language Development