General Rule:
* "Able" is generally used when the root word is a verb. For example:
* Break + able = Breakable
* Chang + able = Changeable
* Understand + able = Understandable
* "Ible" is generally used when the root word is a noun or adjective. For example:
* Access + ible = Accessible
* Divis + ible = Divisible
* Respons + ible = Responsible
Exceptions and Considerations:
* Latin Roots: Many words with "ible" endings come from Latin roots.
* Aud + ible = Audible (from Latin "audire" - to hear)
* Vis + ible = Visible (from Latin "videre" - to see)
* Double Consonant: If the root word ends in a consonant and the suffix "-able" would create a double consonant, it often changes to "-ible" to avoid the awkward pronunciation.
* Permiss + ible = Permissible (not "permissable")
* Pronunciation: Ultimately, the choice often comes down to pronunciation. Choose the ending that sounds most natural.
Tips to Help Remember:
* Think of common words: Words like "comfortable," "readable," and "changeable" help you remember the basic pattern.
* Use a dictionary: If you're unsure, always refer to a dictionary.
It's important to note: The rules about "able" and "ible" are not absolute. There are exceptions, and sometimes the choice depends on the specific word and its pronunciation.