According to the philosophy of composition, why did poe choose nervermore as the refrain in the raven?

Because of the sounds of the "o" and the "r"

Explanation:

"Philosophy of Composition" is an essay written by Edgar Allan Poe in which he attempts to explain a theory about how good writers write when they write well. Poe uses his own composition from the poem "The Crow" as an example. In this essay, Poe explains why he chose the word "nervermore" as the chorus of "The Raven."

Poe considered that the chorus of "The Raven" should be a small word that brought a certain monotony of sound but renewed its meaning with each repetition. Poe also wanted the word used in the chorus to have a fortee sound that was susceptible to prolonged emphasis, with the loudest vowel among the vowels associated with the letter "R". The loudest vowel in Poe's consent was the letter "O", so we can define that the word "nevermore" was chosen because of the association between the letters "O" and "R".