Studies have shown that signing does not delay speech. However, often parents who did not feel compelled to sign with their child at first did start signing when a speech delay was noticed. Similarily, many parents of children who have delays such as Down syndrome choose to sign with their child because they know that speech delays are common in children with certain disabilities.

Our son has Down syndrome and was able to sign more than 300 signs at age 2. Now he is 4 and talks up a storm (he is very verbal which is not always common for children with Down syndrome). Our one year old also knows a lot of sign and also talks a lot.

One thing we did a LOT of though was we always SAID the word slowly and clearly when we signed it. We also did a lot of our signing at face level so that attention could be drawn to the mouth so that our children could see our lips while watching the sign.