Able vs. Ible – Which is Correct?

The choice between the suffixes -able and -ible often causes confusion, but understanding their origins and typical applications can clarify which to use. Both suffixes turn verbs into adjectives, meaning “capable of” or “worthy of” being something. Generally, -able is the more common and productive suffix, often attaching to complete English verbs, while -ible typically attaches to Latin root words that are not standalone English verbs.

-able or -ible – Which is Correct?

Both -able and -ible are correct and valid suffixes in the English language, but they are not interchangeable. The decision of which to use primarily depends on the root word’s origin and structure. The suffix -able is largely Germanic or Old French in origin and is typically added to complete English verbs or nouns to form an adjective. For example, from the verb “wash,” we get “washable.”

In contrast, the suffix -ible is directly from Latin and is usually added to Latin root words that do not stand alone as complete English verbs. These words often entered English through French or directly from Latin. For instance, the Latin root “audire” (to hear) gives us “audible,” where “aud” is not a standalone English verb.

The Best Trick to Remember the Difference

A helpful trick involves trying to remove the suffix and see if the remaining part is a complete English word. This isn’t foolproof but works for many common instances:

• The “Drop-the-Suffix” Test: If you can remove -able and be left with a recognizable, standalone English verb, then -able is likely the correct choice.
  • Example: “manageable” → “manage” (a complete verb)
  • Example: “readable” → “read” (a complete verb)
• The “Latin Root” Indicator: If removing the suffix leaves you with a fragment that is not a standalone English verb, it’s often a sign that -ible is required, indicating a Latin root.
  • Example: “audible” → “aud” (not an English verb)
  • Example: “visible” → “vis” (not an English verb)

While this trick is useful, remember there are exceptions, and some words derive from Latin roots that also happen to be complete English words (e.g., “capable” from Latin “capere” where “cap” isn’t a verb). When in doubt, consulting a dictionary is always the most reliable method.

Suffix	Typical Use	Meaning	Example
-able	Added to complete English verbs or nouns. More productive.	Capable of being; worthy of.	Enjoyable (from “enjoy”): capable of being enjoyed.
-ible	Added to Latin roots that are not standalone English verbs.	Capable of being; worthy of.	Sensible (from Latin “sensum”): capable of being perceived or making sense.

When to Use the Suffix -able

The suffix -able is highly versatile and is the more common of the two. It is used to form adjectives from a wide range of words, primarily complete English verbs. When you add -able to a verb, it generally means “capable of being [verb-ed]” or “worthy of being [verb-ed].” This suffix is considered “productive,” meaning it is still actively used to create new words in English today.

Example 1: “The new software is incredibly adaptable to different user needs.”

Example 2: “This material is completely washable, which is great for children’s clothes.”

Example 3: “His explanation was very understandable, even for beginners.”

Words Formed with -able

Many common adjectives in English are formed with -able. Here are a few examples:

• Adjustable: Capable of being adjusted. (from “adjust”)
• Breakable: Capable of being broken. (from “break”)
• Fashionable: Conforming to current fashion. (from “fashion” – a noun)
• Likable: Easy to like; pleasant. (from “like”)
• Manageable: Capable of being managed or controlled. (from “manage”)
• Portable: Capable of being carried or moved. (from “port” – Latin root, but often seen as an English verb in compounds like “transport”)
• Reliable: Capable of being relied upon; dependable. (from “rely”)

Etymology of the suffix -able

The suffix -able comes from Old French -able, which itself derived from the Latin suffix -abilis. In Latin, -abilis was used to form adjectives from verbs, indicating capability or suitability. English adopted this suffix through Norman French, and it quickly became a highly productive element for creating new adjectives.

When to Use the Suffix -ible

The suffix -ible is less common than -able and is typically reserved for words that come directly from Latin or French, where the root word is not a standalone English verb. Like -able, it also means “capable of being” or “worthy of.” However, its usage is more constrained by the etymology of the root word.

Example 1: “The sound was barely audible over the roar of the crowd.”

Example 2: “It’s important to be sensible when making financial decisions.”

Example 3: “The magician’s trick was truly incredible.”

Words Formed with -ible

Words formed with -ible often sound more formal or academic due to their direct Latin heritage. Here are some examples:

• Audible: Capable of being heard. (from Latin “audire” – to hear)
• Combustible: Capable of catching fire and burning. (from Latin “comburere” – to burn up)
• Edible: Fit to be eaten. (from Latin “edere” – to eat)
• Flexible: Capable of bending without breaking. (from Latin “flectere” – to bend)
• Invincible: Incapable of being conquered. (from Latin “vincere” – to conquer)
• Permissible: Allowable; permitted. (from Latin “permittere” – to allow)
• Visible: Capable of being seen. (from Latin “videre” – to see)

Etymology of the suffix -ible

The suffix -ible comes directly from the Latin suffix -ibilis. This Latin suffix was used to form adjectives from certain types of Latin verbs, particularly those of the third and fourth conjugations. When Latin words were borrowed into English, either directly or through Old French, they often retained this original suffix, leading to the -ible form we see today.

Related Concepts

Understanding broader linguistic concepts can help solidify your grasp of suffixes like -able and -ible.

• Suffixes: A suffix is a letter or group of letters added to the end of a word to form a new word or to change the word’s grammatical function. In this case, -able and -ible are adjective-forming suffixes.
• Etymology: The study of the origin and historical development of words. Knowing a word’s etymology often explains why it takes one suffix over another, particularly for Latin-derived words.

Examples from Media and Literature

• “It was a truly remarkable achievement, one that would be remembered for generations.” (using -able)
• “The silence in the old house was almost palpable, thick with unspoken secrets.” (using -able)
• “Her laughter was so infectious, making the whole room feel more enjoyable.” (using -able)
• “Despite the challenges, a peaceful resolution seemed entirely possible.” (using -ible)
• “The old manuscript was barely legible, its ink faded with time.” (using -ible)
• “He found her arguments quite plausible, even if he didn’t entirely agree.” (using -ible)

Practice Exercises

Choose the correct suffix (-able or -ible) to complete the word in each sentence.

1. The company’s new policy is very access______.
2. Her story was so incred______ that no one believed her.
3. This antique vase is extremely break______, so handle it with care.
4. The politician’s speech was barely aud______ due to the faulty microphone.
5. The fabric is dur______, making it perfect for outdoor furniture.

Answer Key

1. accessible
2. incredible
3. breakable
4. audible
5. durable

Frequently Asked Questions

Question 1: Is there a simple rule for -able vs -ible?
The simplest rule is to try the “Drop-the-Suffix” test: if you’re left with a complete English verb, use -able. If you’re left with a fragment that isn’t a standalone verb, -ible is often correct. However, this rule has exceptions, and many words with -ible simply must be learned as they come from Latin roots that don’t directly form English verbs.

Question 2: Are there exceptions to the rules for -able and -ible?
Yes, English is full of exceptions! Some words derived from Latin roots, like “capable” or “movable,” take -able even though their roots aren’t standalone English verbs. Conversely, some words might seem to fit the -able rule but historically take -ible (e.g., “combustible”). When uncertain, a dictionary is your best resource.

Question 3: Does the meaning change whether I use -able or -ible?
No, the core meaning of “capable of being” or “worthy of” remains the same for both suffixes. The difference lies purely in the etymological rules and conventions of English spelling, not in the semantic contribution of the suffix itself.

Conclusion

While the choice between -able and -ible can seem daunting, remembering their origins provides a strong framework. The suffix -able is the more common, productive one, typically attaching to complete English verbs. The suffix -ible, on the other hand, usually signals a direct Latin root that isn’t a standalone English verb. Developing an awareness of these patterns, along with a healthy habit of consulting a dictionary, will help you navigate these suffixes with greater confidence. Pro Tip: Correct usage of these suffixes enhances your professional credibility and ensures your written communication is clear and precise.