"All things," said Caroline, "would not necessarily communicate by sound.
That's just one way of making yourself understood. There would be many other ways. These things make sounds, but that doesn't mean they would have to talk with sound. They may have no auditory apparatus. They may not even know that they make sounds, might not know what sound is.”
"They're back again," said Gary. "You try this time. Try thinking at them.
Pick out one of them and concentrate on him.”
A minute passed, a minute of utter silence.
"It's funny," said Caroline. "I couldn't reach them at all. There wasn't even a flicker of response. But I had the feeling that they knew and that they rejected what I tried to tell them. They closed their minds and would not listen.”
"They don't talk," said Gary. "And they either can't or won't telepath.
What's next?”
"Sign language," Caroline said. "Pictures after that. Pantomime.”
But it did no good. The goblins watched with interest when Gary tried sign language. They crept close to watch as he drew diagrams in the sandy soil.