Spelling -able & -ible
Spell words ending in -able/-ible and the corresponding adverb forms -ably/-ibly, applying patterns to determine which suffix to use based on the root word
What a learner can do afterwards
- Apply the guideline that -able is typically used with complete root words (enjoyable, comfortable) while -ible is used with incomplete roots (visible, possible), noting key exceptions
- Convert -able/-ible adjectives into adverbs by changing the ending to -ably/-ibly, e.g. comfortable → comfortably, possible → possibly, terrible → terribly
- Determine whether to drop or retain the final -e of the root when adding -able, e.g. adorable (drop e) vs changeable (keep e before soft g)
The lesson
Many words end with the same sound, something like 'uh-bul,' but you spell it two different ways: -able or -ible. Look at the root, the part before the ending, to pick the right one. If the root is a whole word you already know, like enjoy or comfort, add -able: enjoyable, comfortable. If the root is not a whole word by itself, like vis or poss, add -ible: visible, possible.
Adore ends in a silent e. Drop the e before adding -able: adore becomes adorable. Change also ends in e, but that e keeps the g sound soft. Drop it, and changeable would look like it should rhyme with the hard g in 'go.' So change keeps its e: changeable.
To turn these words into adverbs, swap the final e for y. Comfortable becomes comfortably. Possible becomes possibly. Terrible becomes terribly.
The whole-word rule is a guideline, not a promise. Flex is a whole word, but the correct spelling is flexible, not flexable. When you are not sure, check a dictionary.
Complete root plus -able, incomplete root plus -ible, and swap the e for y to spell the adverb, but watch for exceptions like flexible.
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