Updated: Aug 23, 2021
Sometimes, when we want to add a suffix, like ‘ing’ or ‘ed’ to an English word, we double the consonant that comes before it:
For example - run becomes running.
However, sometimes we keep the spelling of the root word the same, without adding a double consonant:
For example - pick becomes picking.
So knowing when to use a double or single consonant in English spelling can seem confusing.
It’s really important to get the spelling right when we add a suffix because if we don’t we can write completely the wrong word down.
For example, hope can become hoping or hopping!!
Let’s look at four rules that will help you to understand whether or not to double a consonant in English. As we go through the rules, you will notice that they are related to how the word sounds when it is spoken out loud.
Rule #1 - consonant, short vowel, consonant
Many short english words are made up of a consonant, a short sounding vowel, and then another consonant. By short sound we mean a,e,i,o,u instead of a,e,i,o,u
Here are some examples:
bat - which uses the short ‘a’ sound
wet - which uses the short ‘e’ sound
Sit - which uses the short ‘i’ sound
hop - which uses the short ‘o’ sound
Put - which uses the short ‘u’ sound
So, rule #1 - if we want to add a suffix (such as ‘ing’) to these kinds of words, we do need to double the last consonant.
bat becomes batting
wet becomes wetting
sit becomes sitting
hop becomes hopping
put becomes putting
This rule will also work for longer english words that are made up of just one syllable. For example stop, or grab.
The rule works because these words are still using the short form of the vowel sound:
Stop - which uses the short ‘o’ vowel sound between two consonants, becomes stopping.
Grab - which uses the short ‘a’ vowel sound between two consonants, becomes grabbing.
Rule #2 - consonant, short vowel, double consonant
Rule #2 builds on the what we covered in rule #1.
Rule #1 - consonant/ short vowel / consonant
Rule #2 - consonant/ short vowel / double consonant
This time, we’re going to see what happens when a root word starts with a consonant, uses a short vowel but then has a double consonant.
In these cases, we do not need to double the final consonant when adding a suffix.
The root word stays the same:
Last becomes lasting
Pelt becomes pelting
Link becomes linking
Jump becomes jumping.
Remember, there are always exceptions to rules like this in english, for example with irregular verbs. Don’t worry too much about this for now, you will learn these exceptions with time and practice.
Rule #3 - consonant, long vowel, consonant
So far, we’ve looked at the rules for short words that use a short vowel sound.
Now, we’re going to look at words that use a long vowel sound a,e,i,o,u:
Consonant / long vowel sound / consonant
Here are some example regular verbs that follow that pattern:
hate - which uses the long ‘a’ sound
heat - which uses the long ‘e’ sound
rise - which uses the long ‘i’ sound
hope - which uses the long ‘o’ sound
suit - which uses the long ‘u’ sound
If we want to add a suffix (such as ‘ing’ or ‘ed’) to these words that use a long sound vowel , we do not need to double the last consonant.
hate becomes hating or hated
heat becomes heating or heated
size becomes sizing or sized
hope becomes hoping or hoped
suit becomes suited or suiting
Notice that if the root word ends in an ‘e’ - such as in the words hate, size, and hope - this is dropped before the suffix is added.
Rule #4 - Get stressed!
For our final rule, we’re going to look at when to use double consonants in english words with two or more syllables (or sounds).
To use this rule, you need to pay attention to which syllable is stressed the most when the word is spoken out loud.
Let’s look at an example:
In the word occur - there are two syllables ‘occ’ ‘ur’. The stress or emphasis is placed on the final syllable - ‘ur’. It’s a harder, more dominant sound.
So, if we want to add a suffix, we need to double the consonant in the dominant syllable: occurring or occurred.
Let’s look at another example root word: prefer
When we say this word out loud, we notice that it has two syllables - ‘pre’ and ‘fer’. The emphasis, when we say the word out loud, is on the second sound ‘fer’.
So, if we want to add a prefix, we need to double that second consonant after the vowel. Prefer becomes: preferred or preferring.
If the emphasis is on the first syllable in the word, there is no need to double the consonant.
Here are some examples where we don’t need to double the consonant when adding a suffix to a root word:
Listen - in this word, the emphasis is on the first syllable ‘lis’. So, we don’t need to double the consonant in order to add the suffix - listening or listened.
Let’s work through another example together with the root word ‘happen’.
When we say the root word out loud, the stress is on the first syllable ‘ha’. So, we don’t need to double the final consonant when adding a suffix - happening or happened.
Put your learning to the test
Here is a list of English root words. Apply the rules you have just learned to see if you would need to add a double consonant when adding a suffix: