Baby sign language was one of those really trendy things to do a few years back.
Being as I both don't have an infant nor am I particularly good on staying up with the latest trends, I couldn't tell you off hand whether it still is such an "in" thing to do.
But I do want to tell you that it can be an incredibly useful tool for the toddler years.
The advantage of the baby sign language is that it fills the period of time when a baby wants to communicate but still doesn't have much for language skills.
Now someone uninitiated into parenthood might not understand why a baby being able to sign "eat" would be so important, but you had better believe that stressed out sleep deprived parent who is desperately trying to figure out what their little darling is screaming her head off about would see some merit to that ability.
I came into motherhood knowing exactly TWO baby signs, "more" and "thank you", from my time working in childcare.
But when baby Kristina not only picked them up but started using "more" constantly, I quickly determined that I needed to expand our baby sign language vocabulary.
I got the Baby Einsteins My First Signs DVD, which although certainly not the stuff of our usual tv watching (and certainly not anything that I thought would make her exceptionally smarter, as I'd been rather disdainful of the series in the past), was a very useful thing to teach both of us a reasonable set of useful signs.
I rather doubt Kristina would have learned all of them and then integrated them into her everyday actions had I not also learned and then regularly used them when talking to her. So as the parent you might just have to watch it with them, at least until you can remember the difference between "bath" and "ball".
And the biggest recommendation I can make is for you to either look up or make up signs for whatever other objects/actions your child regularly uses.
Because otherwise your little one will for you, or you will regret their lack of doing so.
Do you know how many children who were nursed into their toddler years made up a word for "nursing"? Ask around some time, you'll hear some good ones.
(Tatas is more personal favorite, although nuz nuz and shuffy are also pretty good.)
And in our family, Adrianna loves her pacifier.
So far she communicates her want of it in a three step process: Making loud annoying noises, pointing to where we like to hide them out of her reach, and then pointing to her mouth.
Because she won't say "paci" or give it some other name. And I don't have know the sign for it.