Why are the final consonants in 'idealism' and 'terrorize' not doubled?

The reasoning behind why the final consonants in 'idealism' and 'terrorize' are not doubled rests on syllable stress patterns in the words. When adding suffixes to a base or root word, English spelling rules dictate that a final consonant is typically doubled only when the stress is on the final syllable of the base word and it ends in a single consonant preceded by a single vowel.

In the case of 'idealism', the stress is on the second syllable ('de'), making the final consonant 'l' not subject to doubling when the suffix '-ism' is added. Similarly, for 'terrorize', the stress is on the first syllable ('ter'), again indicating that the final consonant 'r' does not need to be doubled when the suffix '-ize' is applied. This understanding of syllable stress is crucial in determining when consonants should be doubled in English spelling, highlighting the importance of stress in morphology and spelling rules.