Answer:
Break it and it is better, immediately set and harder to break again
I can be written, I can be spoken, I can be exposed, I can be broken.
I am free for the taking. Through all of your life, though given but once at birth. I am less than nothing in weight, but will fell the strongest of you if held.
Half-way up the hill, I see you at last, lying beneath me with your sounds and sights. A city in the twilight, dim and vast, with smoking roofs, soft bells, and gleaming lights.
I don't have eyes, but once I did see. Once I had thoughts, but now I'm white and empty.
I always murmur but never talk. Always run but never walk. I have a bed but never sleep, have a mouth but never speak. What am I?