He used language rich in symbol. Since ''archaeology'' is too long a word to spell out by hand, he expressed it with an inverted sign for the letter A, moved in a digging motion. His reference to The New York Times ended with a quick tap on his wristwatch. Desert people hollowed out eggs to carry water in. Eggshells let oxygen in through their pores.
Male penguins incubate their eggs on the feet, under a flap of skin.
And yes, that fossilized baby dinosaur has a piece of eggshell on its cheek. Mr. Grayson, who learned signing from his deaf parents, said he has even been accused of signing with a Philadelphia accent. He mouths the words he interpret, to help lip-readers, and whispers them as well. But the signs are the focus, he explained. ''Less than 25 percent of spoken English is visible on the lips,'' he said. So he often wears black while interpreting, to make hands easier to watch.