First, poems are aural compositions. Poets compose their works with the ear in mind. W.H. Auden, a British poet who has been widely anthologized in major collections of poetry, made a case for listening to poems when he said, ''No poem, which when mastered, is not better heard than read is good poetry.'' In other words, good poetry works better through the ears than through the eyes.
Poets develop an ear for the musicality of language, and that's why we have so many words for the acoustic effects in poetry. Acoustics refers to the sounds in a poem. Words not only deliver a meaning, but they deliver a sound as well. As an example, let's think about the word ''crackle.'' The word refers to a series of popping sounds, and when you say it aloud, you actually hear those popping sounds from the hard ''c'' and ''k.'' This word shows onomatopoeia, the poetic term for a word that generates the sound it describes. ''Crackle'' is also a harsh-sounding word. In poetry we call that cacophony. There are many other devices that poets use to describe their skillful manipulation of sounds.
Because poems are meant to be heard, poets have to understand how to manipulate both the sounds and the cadence of poetry. That cadence is called poetic meter, and like the acoustic terms, it's most effective when heard. All language comes in syllables that are either loud or soft. Consider the word ''poetry.'' This word has three syllables, and the first one is much louder than the middle syllable. When a poet utilizes poetic meter, he stacks those loud and soft syllables in a pattern that creates a rhythm, and that rhythm is hard to hear unless the poem is read aloud. Think about looking at sheet music; it takes years of study to ''hear'' the sounds from only seeing the notes. Like sheet music, the music of poems comes through when performed on the instrument of the human voice.
Reading for Understanding
The second reason to read poems out loud is to understand them better. All those subtle sounds and rhythms, those are directly tied to the meaning of the poem. It's much harder to comprehend and interpret a poem without hearing it, or better yet, reading it aloud for yourself. By reading the poem, you take on the role of the poem's speaker, and that will give you insight into the speaker's perspective, which is critical for understanding a poem.