What does word stress in pronunciation refer to?

Word stress in pronunciation refers to the emphasis placed on certain syllables within a word, which is typically marked by a change in pitch, volume, or length of the vowel sound in that syllable. This emphasis can significantly affect the meaning of words, as different words can have different meanings based on which syllable is stressed. For instance, in the word "record," the noun form has the stress on the first syllable (RE-cord), while the verb form has the stress on the second syllable (re-CORD).

The correct answer captures the essence of word stress by highlighting that it is not merely about emphasizing consonants or altering the timing and rhythm of speech; it specifically involves the emphasis on syllables that usually contains a vowel sound. The emphasis is essential in conveying meaning clearly in spoken language, making it a critical aspect of pronunciation for language learners. Understanding word stress also aids in improving one's intelligibility and fluency in a second language, which is particularly relevant for English language learners.