Here's why we can't say a suffix *is* a syllable:
* Syllables are units of sound: They are based on how we pronounce words, not just the letters.
* Suffixes are written units: They are letters that change the meaning or function of a word.
Example:
* "Happy" has one syllable.
* "Happiness" has two syllables, and the "-ness" is a suffix that creates the second syllable.
So, while a suffix might not *always* create a new syllable, it frequently does.