Word stress SIX BASIC RULES

These rules do not cover all the aspects of word stress in English; but they do cover the large majority of plurisyllabic words in the language.

The problem: should you say: DIFficult or difFICult or diffiCULT?Here are the main principles that determine how words are stressed or accentuated in English.

1.   A word is normally stressed on the first syllable, unless there is a reason to put the stress somewhere else.

1. The "reasons" are either suffixes (like -ity or -ion)
or prefixes (like con-, dis-, ex- or in-).

3- If the suffix (ending) starts with the letters i or u this will affect
the position of stress in a word. 
Sample suffixes: -ion, -ual, -ial, -ient, -ious, -ior, -ic, -ity, etc. 
the stress comes on the syllable before the suffix. 
Examples: Atlantic, comic, sufficient,
explanation, residual.

There are only a very few exceptions to this rule.