Stressed syllables sound louder, are usually longer, and have clearer vowels and stronger consonants. In a word said in isolation, stressed syllables are higher pitched; in sentences, a pitch change (a change in melody from high to low or low to high) often occurs on stressed syllables.
Unstressed syllables sound softer, are usually shorter, and are frequently reduced or centralized. This means that the vowels tend to become /ə/, /ɪ/, /ɚ/, or /ʊ/, and the consonants are weaker. The pitch doesn’t change direction on unstressed syllables.
Stress falls two syllables before these suffixes.
Important Exceptions:
-tary
təri