Question

why might prosody change the meaning of a sentence?
because the words change spelling when spoken
because tone, stress, or pauses can show emotion or intention
because louder voices always mean anger
because grammar rules disappear in speech

Explanation:

Prosody refers to the rhythm, stress, and intonation in speech. Tone, stress, or pauses (which are aspects of prosody) can convey emotion or intention. For example, a rising tone at the end of a sentence can indicate a question (showing intention), and stress on a particular word can emphasize its importance (which may relate to emotion or intention). Grammar rules are more about the structure of language (like subject - verb agreement) and not directly about prosody. Louder voices are not the only way prosody works (and "always" is too absolute). Words changing spelling when spoken is more about phonetics and not prosody.

Answer:

Because tone, stress, or pauses can show emotion or intention.