How does stress primarily affect prosody in speech?

Stress primarily affects prosody in speech by changing vowel characteristics in stressed syllables. When a syllable is stressed, the vowel within that syllable typically becomes more prominent. This prominence can be manifested as an increase in loudness, heightening of pitch, and lengthening of the vowel, making it more distinct from unstressed syllables. The change in vowel quality is crucial because it not only affects how easily the words are understood but also conveys emotion and nuance in spoken language.

In contrast, while pitch and loudness can also be altered, these changes are more about the overall quality of the stress rather than specifically focusing on consonants. Additionally, stress does not inherently reduce the length of phonemes; instead, stressed syllables tend to have longer durations than unstressed syllables. Likewise, simplifying sentence structures does not directly connect with how stress operates in a phonetic context; it pertains more to syntax rather than prosody in speech. Thus, focusing on how stress modifies the characteristics of vowels in stressed syllables highlights the primary way prosody is affected in speech.