All important suffix rules in English

Categories: Basic English

English Suffix Rules

1. General Rule

A suffix is added to the end of a base word to change meaning or part of speech.

• teach → teacher

• happy → happiness

• care → careful

2. Doubling Consonants Rule (CVC Rule)

A. One-syllable words ending in consonant-vowel-consonant (CVC)

➡ Double the final consonant when adding -ed, -ing, -er, -est.

• run → running, runner

• sit → sitting

• hop → hopped, hopping

• big → bigger, biggest

⚠️ Exception: Do not double w, x, y.

• snow → snowing (not snowwing)

• play → playing

B. Multi-syllable words, stress on last syllable, ending in CVC

➡ Double final consonant.

• begin → beginning

• admit → admitted

• prefer → preferred, preferring

⚠️ If stress is not on last syllable, don’t double.

• open → opening (not openning)

• visit → visited (not visitted)

C. British English vs American English (words ending in -l)

• BrE doubles “l” before vowel suffixes: travel → travelling, cancelled

• AmE uses single “l”: travel → traveling, canceled

3. Dropping Final “-e”

A. Drop final silent “-e” before vowel suffixes (-ing, -ed, -er, -est, -able, -ous).

• make → making, maker

• hope → hoping, hopeful

• drive → driving, driven

• use → usable

B. Keep final “-e” before consonant suffixes

• hope → hopeful

• care → careless

C. Exceptions

• change → changeable (keep “e” for pronunciation)

• manage → manageable

• dye → dyeing (to avoid confusion with dying)

4. Changing Final “-y” to “-i”

A. Change “y” to “i” before non-vowel suffixes

• happy → happiness

• beauty → beautiful

• try → tried

• carry → carried

B. Do NOT change “y” before “-ing”

• try → trying

• cry → crying

C. Words ending with vowel + y

➡ Keep “y”.

• play → played, playing

• enjoy → enjoyment

5. Words Ending in “-c”

➡ Add “k” before suffixes starting with e, i, y.

• panic → panicked, panicking

• mimic → mimicked

• picnic → picnicking

6. Words Ending in “-ie”

➡ Change “ie” to “y” before adding “-ing”.

• lie → lying

• die → dying

• tie → tying

7. Suffix Meanings (Common Groups)

a. Noun Suffixes

• -ness (state/quality): happy → happiness

• -ment (result): develop → development

• -er / -or (person/thing): teach → teacher, act → actor

• -tion / -sion (action/result): educate → education, decide → decision

b. Adjective Suffixes

• -ful (full of): care → careful

• -less (without): hope → hopeless

• -ous (having): danger → dangerous

• -able / -ible (capable of): read → readable, flex → flexible

c. Verb Suffixes

• -en (make): short → shorten

• -ize / -ise (cause to be): modern → modernize, realize/realise

• -ify (make): pure → purify

d. Adverb Suffixes

• -ly (in a manner): quick → quickly, slow → slowly

8. Special Notes & Exceptions

1. Irregular forms

   • good → better, best (not “gooder”)

   • bad → worse, worst

   • child → children (not “childs”)

2. Double suffixes

   • hope → hopelessness

   • care → carefully

   • beauty → beautiful → beautifully

3. Silent “e” retention

   • singe → singeing (to distinguish from singing)

   • age → aging (AmE), ageing (BrE)

✅ Summary of Main Rules

• Double consonant in CVC pattern (run → running).

• Drop silent -e before vowel suffixes (make → making).

• Keep -e before consonant suffixes (hope → hopeful).

• Change -y → i (happy → happier, but play → playing).

• Add -k after -c before e/i/y (panic → panicked).

• Change -ie → y before -ing (die → dying).