The Spelling Rules for Adding Suffixes:
When to double a letter - and when not to double

think back to spelling teaching Remember -
This is when we do need to double:

The second vowel is like an invader. He is trying to attack the short vowel and make it change its ways. If he can get near enough, he will make it say its long sound. Help spelling Rules for Adding Suffixes

Here, there is a strong wall of two consonants. This will protect the short vowel from attack. The invader can't get close, so the first vowel can carry on as before.
Help spelling Rules for Adding Suffixes

Teaching point - learning to spell The invader only attacks short vowels!

The long vowels are safe - by making a long sound,they are already doing what he wants, so there is no need to attack! Help spelling Rules for Adding Suffixes

Also, any time there are two vowels together he will not bother to attack, whatever the sound. Think of it as 'safety in numbers' - he wouldn't dare to attack when he is outnumbered!
Help spelling Rules for Adding Suffixes

Some more examples:

sailing hooter deepest groaned header shouting boiler

...and never double w :

showing fewest drawer

Now try these. Again, they are a mixture; you will need a double consonant in some words.

Ask yourself:

  • Do I need to protect a short vowel?
  • Will there be a wall of two consonants if I need it?

Add the suffix to the root word

Type the answer

plain + er
boat + ing
slip + ed
dream + er
creep + y
deaf + en
ship + ment
mix + ing
grab + ed
chill + y
limp + ing
grow + ing


Skip this exercise and go to the next part of this unit: When do we drop the letter e? *

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Unit 9: Adding suffixes: the spelling rules

Page 8 of 19

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