Trisyllabic laxing is a process in English which affects tense vowels and diphthongs. They become lax in word formation when followed by two or more syllables and the first syllable is stressed. The process first occurred in Old English.
Here are examples of trisyllabic laxing:
In the cases of denounce, pronounce and renounce, the lax vowel in the nouns denunciation, pronunciation and renunciation does not carry primary stress but rather secondary stress. This stress shift is also evident in word pairs such as civilize/civilization, organize/organization and realize/realization. In these word pairs, however, trisyllabic laxing is optional.
Trisyllabic laxing has exceptions. The process does not apply in the following words:
The rule of trisyllabic laxing applies to many English words. The process first developed in Old English and affects tense vowels and diphthongs. They become lax when they are stressed and are in the third syllable or farther from the end of the derived form. However, this rule has exceptions.