Word stress is your magic key to understanding spoken English. Native speakers of English use word stress naturally. Word stress is so natural for them that they don't even know they use it. Non-native speakers who speak English to native speakers without using word stress, encounter two problems:

  1. They find it difficult to understand native speakers, especially those speaking fast.
  2. The native speakers may find it difficult to understand them.

Understanding Syllables

To understand word stress, it helps to understand syllables.
Every word is made from syllables.
Each word has one, two, three or more syllables.

word number of syllables
dog dog 1
green green 1
quite quite 1
quiet qui-et 2
orange or-ange 2
table ta-ble 2
expensive ex-pen-sive 3
interesting in-ter-est-ing 4
realistic re-al-is-tic 4
unexceptional un-ex-cep-tion-al 5

Notice that (with a few rare exceptions) every syllable contains at least one vowel (a, e, i, o or u) or vowel sound.