Answer:
I fill a room but take no space.
I can speak with my hard metal tongue. But I cannot breathe for I have no lung
I am the key that is the hardest to turn
While you were folding a letter you got me. Usually you will do whatever it takes to avoid me but now you can't help but find me.
I can sizzle like bacon, I am made with an egg. I peel layers like onions, but still remain whole. I can be long, like a flagpole, yet fit in a hole. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.