Quick: what’s the sound of one grasshopper speaking? If you said “cheep, cheep,” give yourself… half credit. This poem is letting us know that the sounds of the natural world are, in fact, important (if figurative) voices. Every element in nature, in other words, has the power to speak to us—if only we listen closely enough.
Lines 1, 2, 3, 6, 7, 8, 9, 12: The word “voice” is repeated nine times in a poem that’s only twelve lines long. Do you still think it’s not an important symbol of the natural world? This is a poem about the power of the “voices” of nature, and that power is emphasized through repetition of the word itself in the poem.