-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)
|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|
|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.