How does prosody shape the rhythm and sound of a poem?

Prosody is the study of the elements of language that contribute to the acoustic and rhythmic effects of a poem, encompassing what poet Ezra Pound described as the "articulation of the total sound of a poem". It shapes a poem's rhythm and sound through several key mechanisms:1

• Metre: This is a primary method of organizing rhythm by creating a formal pattern of stressed and unstressed syllables, duration, or syllable counts. In English, the most common form is accentual-syllabic verse, which balances stress and syllable counts to create consistent rhythmic structures like iambic pentameter.23
• Sound Devices: Beyond metre, prosody considers the quality, pitch, and force of sounds. Techniques such as alliteration, assonance, consonance, and rhyme are used to reinforce or provide counterpoint to the underlying metrical pattern.3
• Free Verse: In poetry without a strict metrical scheme, prosody focuses on other linguistic elements to create rhythm, such as natural speech cadences, syntactical patterning, line length, and the use of caesura to manage pace.2

Ultimately, prosody integrates these elements to match the poem's content and emotional tone, creating a "tension" or "counterpoint" that defines the poem's unique movement.23