Found out about this thanks to
One of my favorite short stories when I was younger, has been made into a short film. 
They are made out of meat.
“I thought you just told me they used radio.”
“They do, but what do you think is on the radio? Meat sounds. You know how when you slap or flap meat, it makes a noise? They talk by flapping their meat at each other. They can even sing by squirting air through their meat.”
I first read this story when it appeared in OMNI. I think I was either in junior high, or a freshman in high school. I loved it so much that I cut it out of the magazine and pinned it up on my bulletin board.
I was a nerd then, too.