Scenario 1: Root word is already complete and the "i" is part of a syllable
In this case, you'd treat the root word like any other and apply suffixes as usual. Examples:
* Angry: add "-ly" to make "angrily"
* Happy: add "-ness" to make "happiness"
* Busy: add "-er" to make "busier"
Scenario 2: Root word is a base form and the "i" requires adjustment
This is more complex because you need to consider how the "i" might change in combination with the suffix. Here are some examples:
* If the suffix begins with a vowel:
* Radiate: add "-ing" to make "radiating" (notice the "e" is dropped)
* Flier: add "-s" to make "fliers" (notice the "i" changes to "ie")
* Apply: add "-ing" to make "applying" (notice the "y" changes to "i")
* If the suffix begins with a consonant:
* Fly: add "-er" to make "flyer" (notice the "y" changes to "ie")
* If the suffix is "-es":
* Baby: add "-es" to make "babies"
Important Notes:
* Dictionaries are your best friend! They'll show you the correct spelling of words with suffixes.
* Pay attention to pronunciation. Sometimes spelling changes are based on how the word is pronounced.
* There are exceptions! The English language is full of them. Some words have unique ways of adding suffixes.
In summary, the specific suffix you can add to a root word ending in "i" depends on the word itself, its meaning, and the pronunciation of the resulting word.