Answer:
I am constantly overlooked by everyone but everyone has me.
I am expelled from you orally with a sound
They come out at night without being called. They are lost in the day without being stolen. What are they?
Never resting, never still. Moving silently from hill to hill. It does not walk, run or trot. All is cool where it is not. What is it?
I run smoother than any rhyme, I love to fall but cannot climb. What am I?
Whoever made me don't want me. Whoever bought me don't need me. Whoever use me don't know me.