What Am I? Riddle Inference

Oliver has a knack for puzzles and enjoys spending his afternoons working on different kinds of brain teasers. Recently, he discovered a book that contains a collection of riddles and logic games. He was particularly drawn to one riddle that read, "I speak without a mouth and hear without ears. I have no body, but I come alive with the wind. What am I?" Determined to figure this out, Oliver spent a large part of his afternoon trying to solve it. After considering various possibilities, he took a break and went outside for a walk to clear his mind.

On his walk, he noticed the trees swaying gently and the leaves rustling in the breeze. As he sat on a bench to think, he suddenly realized the answer to the riddle. He was thrilled to connect his time in nature to his love for puzzles.