When people speak English, they don't say every word and every part of each word with the same speed, pitch, and loudness. English has patterns of stress, which means saying some sounds louder and stronger. There are two kinds of stress: stress within words and stress within sentences.

Stress within words

Each word is made up of syllables. A syllable is made of a vowel sound (a, e, i, o, u) and the consonant sounds that come with it. For example, the word "example" has 3 syllables:

ex   am   ple

In every word, there is one syllable that is the most stressed:

ex   AM   ple

In longer words, there can be more than one stressed syllable, but there's always one syllable that has the biggest stress:

mis   un   der   STAN   ding

Stress within words is something that you should learn when you are learning new words. Pay attention to how the word is being said and try to copy how loudly different parts of the word are said.  Using correct stress within words makes it easier for a listener to understand what you're trying to say.

Stress within sentences

Stress within sentences is even more important than within words because it can actually change the meaning of the sentence. Here are some simple rules for how you use stress:

• Stress the word that is the topic of your sentence. If you say "I don't know who THAT is," you are suggesting that there is someone else who you do know. On the other hand, if you say, "I DON'T know who that is," you are emphasizing that you don't know it, although someone might think you do.
• When you are pointing out things that are different from what someone else said, or from what you said in the previous sentence, you should stress the parts that are different. For example, if someone said, "I love cheese" you might say "I love BEER". The word "I" is stressed because it's referring to a different person (you, not the person who said "I love cheese." The word "beer" is stressed because it's different from "cheese".
• Nouns, verbs, and adjectives are stressed more than words like "to", "of", "will", "that", "is", "about".  For example, here's how a normal sentence would be stressed: "This MORNING I WOKE up at SEVEN THIRTY and was OUT of the HOUSE by EIGHT."