Hi Isabel,
we tried to do the baby sign language, but it did not really seem to work for us. We probably gave up too early, but DD did start to learn one sign, "milk" but did that for everything and did not seem to learn any other signs, we also found that a lot of the signs seem like normal behaviours for a baby, so we were confused whether she was attempting a sign or just pointing to her mouth or waving her hand or whatever.I hope this helps. Good luck!