In other words, early delays don’t necessarily translate into a meaningful disadvantage for kids.

Of course, if there is no such delay for sign language, the issue is moot.

A cute anecdote (not related to the empirical merits of signing):

We had a delightful period when my daughter was learning animal sounds (before she really had words as such), and she was also learning basic signs. She kind of mangled the gesture for drink so it looked just like the gesture she made for elephant (miming having a trunk). We only knew the difference because the cup gesture had no sound, and the elephant gesture had a sort of roar accompanying it.

Now (at 20 months), she’s pretty much exclusively verbal rather than gestural, except for the more universal gestures like pointing and waving goodbye.

Some day I will learn to proofread

My son was taught basic sign very early. He was resistant to use it, despite giving indications he understood and could even replicate it. At 18 months I stated requiring he use “milk” (which we knew he was capable of) before nursing, and he stubbornly opted to wean instead. By age 2.5 he started inventing his own signs (like poking a finger into a fist for “ice cream cone” – ah, the tribulations of a toddler inventing his own symbols!), and when we were lucky we’d figure them out and adopt them, but often, we were left just as baffled as before.

He’s 3.5 now and still not using English effectively. He’s got the intonation and tonalities down, he babbles at us constantly and even quotes/sings along with movies. But the consonants aren’t there, and he often “invents” words. For “more” he has persistently tried to use “siu”, for “mom” he uses “da-deh” or “da” for short, “dad” is “guy”, “cat” is “Autumn” (the name of our feline slow and dumb enough for him to pester), flying vehicles real and imaginary are “coo” (truncated “helicopter”? Maybe?). He does have “real” words as well – car, movie, TV, down, home, ball, no, etc. (”Yes” he only signs, though he will verbalize “uh huh”.) He seems to understand the value of speaking to communicate. He doesn’t seem to agree with our opinion that using ENGLISH to speak is necessarily the best option.

With his speech being as spotty as it is, I can’t imagine the kind of frustrated we’d all be if he didn’t have sign.

I think the idea of “delay” is interesting, when some kids just do things a little differently. My husband’s mother was a speech teacher. She gave my husband a test when he was little to see how he was developing. He scored borderline retarded. A week later he was speaking in full sentences. He graduated from an Ivy League school.

From: http://smartbabysignlanguage.blogspot.com/2008/11/will-baby-sign-delay-speech-development.html

“In 1999, Dr. Kimberlee Whaley published the results of her study of hearing infants communicating with sign language in an Ohio State laboratory daycare… The study found that learning baby sign did not slow the children’s speech.”

I have heard, from colleagues whose specialty is closer to the topic (I’m a linguist, but don’t study child language acquisition), that the “bilingual advantage” (the cognitive benefits to people of growing up bilingual) does not work the same in “bimodal bilingualism”. That is, kids who know two spoken languages have more of an advantage than kids who know a spoken and a gestural language. I don’t know the research first-hand, though, so I can’t give more details.