Adding the suffixes -able and -ible:
do the root words change?

-able and -ible are suffixes which change verbs to adjectives.

Follow the rules you know for adding a vowel suffixes.

(To review the suffixing rules, go to Unit 9)

Teaching point 1. If the syllable just before the suffix -able or -ible is the stressed syllable, you will be able to hear a clear short vowel in that syllable. Therefore you will usually need a 'wall' of two consonants to protect that short vowel. For example:
forget + able = forgettable
admit + ible = admissible

2. If the base word ends in e you can usually drop the e, because -able and
-ible both start with a vowel. For example:

excuse + able = excusable
sense + ible = sensible


difficult words, learn not to make mistakes Some root words end in :
-ce with the sound /s/
or -ge with the sound /j/

You need to make sure you do not lose these 'soft' sounds for c and g when you add a suffix. The vowels e, i and y make c say /s/ and g say /j/. The letter a will not do this job so, if the suffix is -able and the ending is -ce or -ge, you must keep the final e of the root word. For example:

service + able = serviceable
manage + able = manageable

Go to next page:
Test yourself on the suffix rules for -able and -ible.

Sign up to remove this advert

Remove this advert

Your current location:

Unit 27: Spelling the endings -able and -ible

Page 8 of 11

Try Spellzone for free



Sign up to remove this advert

I have just finalised the progress of the year groups and am delighted to see that from December to June 53% of the 98 students using Spellzone have raised their standardised scores to 100 and above.

One of the students has put in a huge amount of effort in completing Spellzone at least 3 times a week since his arrival with us in January. Looking at his scores after the latest GL testing, his standardised score has risen from 99 to 131. This is a truly phenomenal result. I just wanted to share the best result I have ever seen.

Terrie Penrose-Toms, Casterton College




We have updated our cookie policy. We use cookies to ensure you get the best experience on Spellzone. Find out more.