“Content” words carry the most meaning in a sentence so receive more stress. They include questions words, nouns, most verbs, adjectives, adverbs, and negative auxiliary verbs (don’t, won’t, hasn’t, etc).
“Function” words give a sentence its grammatically correct form. They carry little meaning so are unstressed. They include articles, pronouns, prepositions, conjunctions, the verb be, and affirmative auxiliary verbs (do, can, did, etc).
Listen to the audio in the podcast down below to understand what words are stressed.