able or ible

Have you ever stopped to think about whether 'dependable' or 'dependible' is right? This confusion comes from the English suffixes -able and -ible. They sound alike but follow different spelling and origin rules. Learning the difference helps you spell better and understand more about how words are formed.

Morphology in Grammar

Now, let's see how morphology, the study of word formation, makes suffixes important. Imagine morphemes as tiny Lego bricks that snap together to form new words and phrases. A morpheme is the smallest grammatical unit in a language that has meaning, such as a prefix, root, or suffix.

Suffixes like -able and -ible transform verbs into adjectives, akin to adding different pieces to a base structure. A base word, in simple terms, is a standalone word to which prefixes and suffixes can be added to modify its meaning. Choosing the correct one often depends on understanding base words and their historical origins.

• The suffix -able means “capable of” or “fit for.” It’s used with complete English base words.

  
  

• The suffix ible also means “able to” or “capable of,” but is more common with words from Latin roots.

  
  

Able vs Ible Words: How to Choose

1. When the Root Word Stands Alone → Use -able

Can the root word stand alone as an independent English word? If yes, choose -able.

Examples:

• comfort → comfortable

• accept → acceptable

• manage → manageable

• understand → understandable

  
  

The original word is still meaningful without the suffix.

2. When the Root Word Doesn’t Stand Alone → Use -ible

If the Latin-based root can't stand alone in English, -ible is usually correct. To remember this, you can think of the mnemonic "Invisible Latin I-ble," which can serve as a little mental tag to help recall the guideline. Imagine a story where a character named 'Ible' comes from an ancient Roman village. Whenever Ible wants to go on adventures in the land of English words, he often finds himself attached to roots that aren't quite complete by themselves, because he's looking for a stable place to fit in that matches his Latin origin.

This way, whenever you see the end of a word like 'visible' or 'flexible,' you'll remember Ible’s journey and his preference for Latin companions.

Examples:

• visible (from Latin videre)

• flexible (from flex)flexible (from flex)

• possible (from possibilis)

• accessible (from accessus)

  
  

3. Keep the Silent e to Preserve the Soft Sound

If a word ends in a soft c or g, keep the final e when adding -able. This preserves the soft sound.

Examples:

notice → noticeable

change → changeable

trace → traceable

Watch the Stress and Short Vowels

If the final syllable of a verb is stressed and has a short vowel, double the final consonant before adding -able or -ible.

However, note some exceptions, such as 'transferable,' which retains only one 'r'. Similarly, 'preferable' and 'referenceable' are exceptions where the final consonant is not doubled. These exceptions occur due to etymological reasons or accepted linguistic conventions that have developed over time. Understanding these peculiarities can help prevent confusion when applying these rules.

Examples:

forget → forgettable

admit → admissible

Practical Tips for Spelling Able/Ible Words

• If you are unsure, use the -able form. It is found in almost 900 modern English words, while -ible appears in about 200.​​ To reinforce your understanding of when to use each suffix, try this simple exercise: Fill in the blanks with either -able or -ible where appropriate. Example words to consider: __________ (comfort), __________ (invis), and __________ (access). This hands-on practice will help solidify the rules in your memory and build confidence in applying them.

• -ible forms are fixed. You cannot create new-ible words today.

Common Able vs Ible Words

Safe Defaults

If you’re in doubt:

• Check if the base word stands alone in English → likely -able.

• Latin root or non-independent base → -ible

• Still unsure? Pick -able. It's safer, more common, and productive.

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Quick Recap

• -able: attached to complete modern base words.

• -ible: older, Latin-derived words.

• Retain “e” after soft c/g.

• Double final consonant when stressed.

• Use “-able” if you are unsure.