Who said "I sound my barbaric yawp over the roofs of the world."?

This quote is attributed to Walt Whitman.

I sound my barbaric yawp over the roofs of the world. - Walt Whitman

"I sound my barbaric yawp over the roofs of the world."

Walt Whitman

Poet American 1819–1892

"Do I contradict myself? Very well then I contradict myself, (I am large, I contain multitudes.)"

"I celebrate myself, and sing myself."

"Keep your face always toward the sunshine, and shadows will fall behind you."

"The future is no more uncertain than the present."