Final answer:
The correct answer to the question is that all words, regardless of whether they are adjectives, verbs, nouns, or pronouns, must consist of at least one syllable to be phonetically expressed.
So, all categories of words must contain at least one syllable to be phonetically expressed.
Step-by-step explanation:
A syllable does not have to be a word, but all words have to be at least one syllable. The correct answer to your question is that all parts of speech, including adjectives, verbs, nouns, and pronouns, must consist of at least one syllable. In English, a syllable is a unit of pronunciation that is typically comprised of a vowel sound with or without surrounding consonants, forming the whole or a part of a word.
For instance, the word 'cat' is both a single syllable and a single word that is a noun. Similarly, 'jump' is a single syllable verb, 'blue' is a single syllable adjective, and 'he' is a single syllable pronoun.
So, all categories of words must contain at least one syllable to be phonetically expressed.