This question submitted from a parent in Russia via http://www.razvitie-pro.ru/методики/Baby-Sign-Language as part of the partnership between Monta Z. Briant and Danone/ Nutricia,Russia, makers of Dannon Yogurt.
Question: Is it for sure that the baby is going to learn how to talk?
Signing won’t inhibit your baby’s language development any more than crawling will inhibit his learning to walk. As a matter of fact, research shows that babies who sign generally talk sooner and build vocabulary more quickly than their non-signing peers. In their 8-year study, Drs. Linda Acredolo and Susan Goodwyn at University of California Davis, found that by age 24 months, the signing babies in the study had 50 more spoken words than the non-signing babies, and by age 36 months, children who signed as babies were talking at the 47-month age level, putting them nearly a year ahead of their non-signing peers.
Think of it this way: Babies learn to recognize the spoken words before they can say them. Once a baby is able to look at a bird and sign BIRD with her hand, she is hearing that word “bird” inside her head, in her thoughts. So, babies are able to learn words, and use them in the correct context, by replacing them with a sign, long before they are able to speak. Once they are physically able to speak, many of them already have quite an extensive vocabulary, ready and waiting to be spoken!
Once your baby is physically developed enough to walk, he’ll no longer crawl, as walking is a much more efficient means of getting from point A to point B. The same is true of signing and talking—once your baby can say a word clearly enough to make his meaning understood, he’ll stop using the sign for that word. Once a child’s vocal apparatus are sufficiently developed, plain talking is a lot easier (and you can even do it with your hands full!).