The technique in English grammar of adding extra emphasis to a syllable or word is called stress. This aids not only pronunciation, it can alter the meaning of a word or shift the purpose of a spoken statement.

Syllable Emphasis in a Word

Only vowels are stressed, not consonants. A word with one syllable can only have one emphasis; words that have two syllables or more will have various accents throughout the word but one emphasis will be the strongest.
When a verb with one syllable has -ing added to it, the verb retains the emphasis, such as in walking, laughing, swimming.
In the examples below, syllables carrying the most emphasis are capitalized.

kang-a-ROO

a-PART-ment

EL-e-phant

COM-fort-er

My-STER-i-ous

Two Syllables

English is a Germanic language but our words come from all over the planet, so there is really no clear-cut general rule on which syllable to emphasize. In some words, though, changing the emphasis changes the entire meaning of the word.

PRES-ent: a gift.

“The biggest present is for you.”

“Any child likes presents.”

Pre-SENT: to give or introduce.

“The new teacher was presented to the class.”

“Bob was presented with the key to his new home.”

OB-ject: anything visible or tangible.

“The object in the sky turned out to be a plane.”

“When it moved, we realized the object on the hill was an animal.”

Ob-JECT: to argue or oppose.

“Your Honor, I object to this witness!”

“Objecting to the rider, the horse started bucking.”

Stress in Conversation

English is called stress-timed language, this can show the beauty of the language. Let’s study the following examples. Emphasis in each example is noted with parentheses. Try saying them out loud to better understand how the main idea of the statement changes.

“A (fine) film.”

“A fine (film)?”

“(What) am I doing?”

“What (am) I doing?”

“What am (I) doing?”

“What am I (doing)?”