English As A Second Language

Consonant doubling

This article refers to British Grammar (American spelling doesn’t always follow the same pattern).

There is a great rule to help you remember when to double the last letter and when NOT to. But it ONLY works in very specific instances. For all others, learners will have to memorise word by word, when to double and when not to.

This is called the Consonant-Vowel-Consonant rule (CVC rule). The following rule ONLY WORKS with VERBS & ADJECTIVES and when using suffixes starting with a vowel. I know it sounds a bit like Chinese but I’m going to show you some examples.

Rule of thumb:

1. Determine what type of word it is? Remember that you can not apply the CVC rule if it is something other than a verb or an adjective. You will have to memorize the world. E.g. Cotton? Baggage? Etc. The phonetic spelling of the word may help you in some cases but once again there is no reliable rule.
2. If it is a verb or an adjective, let’s try the CVC rule. Whenever the last three letters make a CVC pattern and the first letter is a vowel, you can DOUBLE the consonant. Let’s practice.

RUN (R=Consonant, U=Vowel, N=Consonant) = CVC

RUNNING, I=Vowel so we get the right sequence CVC, same for RUNNER

BURN (U=Vowel, R=Consonant, N=Consonant) = VCC which is not the right sequence so we don’t double the consonant. BURNING, BURNER

Type of word        Rule         suffixes starting with        Doubled or Not

Smart                      VCC           wrong sequence                  Smarter / Smartest

Hot                          CVC           Vowel e (CVCV)                  Hotter / Hottest

Big                          CVC           Vowel e (CVCV)                  Bigger / Biggest

Clean                      CVV            wrong sequence                  Cleaning / Cleanest /

Forget                     CVC           Vowel i (CVCV)                   Forgetting

Forget                     CVC            Consonant f                         Forgetful

This rule works for some nouns but don’t take it for granted.

Shop                       CVC             Vowel e & i (CVCV)         Shopping / Shopper

Bag                         CVC              Vowel a (CVCV)              Baggage

And of course they are always exceptions to the rule; life would be too simple otherwise.

Happened, Traveled, Orbited, Edited, Modeled, Budgeted, Gardened, Visited, Blossomed, Benefited, Conquered

Advanced learners

Interesting readings:

A list of common words which obey the consonant doubling rule, words which disobey the doubling rule, words that have doubled consonants for obscure reasons and words with unpredictable endings