Onomatopoeia appears at the beginning and end of poetry. What role does it play in poetry?

First, describe the modality of things truly and naturally, which makes people immersive.

Second, calm down with sound and render a quiet atmosphere.

Third, sound can not only attract readers' attention, but also spread the whole article.

Fourthly, some pictophonetic phrases are selected to synthesize concrete pictures, and the scenery is used to convey the author's strong thoughts and feelings.