The sign language is a good idea. I started it but did not push it.
It's worth doing, even if you don't get signs back. We signed at our DS for months and months and didn't get signs back for what seemed like ages, especially when other parents we knew were getting signs back from their kid at 6 (or even 3) months!
And then, around 14 months, he started signing like crazy. I've since learned that he is the type of kid that will watch and absorb for a long while, and then when ready, delve in and do it like he'd been doing it all along. (He just did this with reading... went from about K-level to 4th-grade level in 3 months.)
My favorite part about him signing was learning very specifically what he was thinking about. We almost never got the "needs" signs (hungry, wet, hurt) and nearly always got identification signs (bird, dog, cat, book). He would wake up in the morning and, first thing, sign "book" (as in, "Read me a book"). Some months later, he would pull my leg by signing things that weren't there. For instance, he'd sign "dog" and point, getting me to look, and then when I'd realize there was nothing there, he'd get this wry smile on his face! Talk about an advanced sense of humor...
