I think of the chimp, the one with the talking hands. In the course of the experiment, that chimp had a baby. Imagine how her trainers must have thrilled when the mother, without prompting, began to sign her newborn. Baby, drink milk. Baby, play ball. And when the baby died, the mother stood over the body, her wrinkled hands moving with animal grace, forming again and again the words: Baby, come hug, Baby come hug, fluent now in the language of grief.