Being a mother of twin boys, we taught them ASL signs with an awesome DVD series starting at 2 months. I believe the DVD series was called 'Baby Signing'Signing Time'. If anything, it was amazing being able to communicate with them sooner which alleviated many frustrations. It bridged a gap until they could start using their words. When they can't say it, they sign it. And eventually, all of their signs have beenwere replaced with words as they make connections to the meanings of more words and their ability to expand their vocabulary continuesthe wordld around them.
At first, we were skeptical because we went 6 months of watching the DVDs and not being able to see any results. Then one day -- they started signing 'milk', 'more', 'eat', 'diaper' all within a week.
I would say it is a judgement call and. I don't believe thatcan't speak for the scientific research on the developmental benefits exceed, however, science aside, the pragmatism of the communication benefits outweigh everything else. Communication sooner leads to connections and meanings to the world around them and opens their world. We have averted many frustrations by having sign language as a tool and we are so happy we stuck towith it.