Sentence Stress Carries Meaning

In a sentence, you stress the words that carry the most information. "I didn't say HE stole the money" means someone else stole it. "I didn't say he STOLE the money" means he maybe borrowed it. Same words, different stress, completely different meaning.

Function words (a, the, is, to, of, and) are almost never stressed. They get reduced to quick, quiet sounds. "I'm going to" becomes "I'm gonna." "Want to" becomes "wanna." This reduction is not laziness — it is the rhythm engine of English.