What the Research Says.

Babies who sign show a larger vocabulary by age two, better sentence structure in the early stages of language development, higher IQ, better social skills, and increased fine motor skills. Most importantly parent and child experience increased bonding.

Dr. Joseph Garcia began to research the use of American Sign Language with hearing babies of hearing parents at Alaska Pacific University in 1987. His thesis research showed that babies who are
exposed to signs regularly and consistently at six to seven months of age can begin expressive communication by their eighth or ninth month. See the book Toddler Talk: The First Signs of Intelligent Life. (Stratton Kehl Publications Inc., 1994) for more of his research and findings.

In the two studies cited below, hearing babies exposed to both ASL and English were able to communicate more complex messages through the use of signs than they could verbally.

• Griffith, P.L. (1985). Mode-switching and mode-finding in a hearing child of deaf parents. Sign Language Studies, 48, 195-222.
• Wilbur, R. and Jones, M. (1974). Some aspects of the acquisition of American Sign Language and English by three hearing children of deaf parents. In La Galy, Fox, & Bruck (Eds.), Papers from the Tenth Regional Meeting of the Chicago Linguistic Society, 742-749.

Dr. Kimberlee Whaley started a longitudinal study in November 1999 to research the use of ASL signs with preverbal babies in a preschool environment. Read more about it.

Marilyn Daniels, professor of speech communication at Penn State University, has researched and written about the use of ASL with infants and preschoolers. Her studies demonstrate that adding visual and kinesthetic elements to verbal communication helps enhance a preschool child’s vocabulary, spelling and reading skills. A great book about this is "Dancing with Words".

• Daniels, M. (2001). Dancing with Words: Signing for Hearing Children’s Literacy. Westport, Connecticut: Bergin and Garvey.
• Daniels, M. (October, 1994). The effects of sign language on hearing children’s language development. Communication Education, 43, 291-298.
• Daniels, M. (1996). Seeing language: The effect over time of sign language on vocabulary development in early childhood education. Child Study Journal, 26, 193-208.

Another useful book on research that found evidence that sign language supports early literacy skills is:
J. Hafer (1986). Signing For Reading Success. Washington D.C.: Clerc Books, Gallaudet University Press.