Spelling Rules for Adding Suffixes

You know that adding suffixes creates new words. But sometimes the base word changes its spelling when a suffix is added. Hope becomes hoping, happy becomes happiness, and run becomes running. These changes follow patterns. In this lesson you will learn four spelling rules that cover most words.

First: vowel suffixes and consonant suffixes

First, notice whether the suffix starts with a vowel or a consonant. This matters for every rule.

• Vowel suffixes: -ing, -ed, -er, -est, -able, -ous, -ion
• Consonant suffixes: -ful, -less, -ness, -ment, -ly

Rule 1: drop the silent e

When a word ends in a silent e, drop the e before adding a vowel suffix. Keep the e before a consonant suffix.

Common exceptions

Words ending in -ce or -ge keep the e before -able or -ous to keep the soft sound: noticeable, courageous, manageable. And argue + -ment drops the e to make argument.

Rule 2: change y to i

When a word ends in a consonant + y, change the y to i before adding most suffixes.

• happy → happiness, happily, happier
• beauty → beautiful
• carry → carried

But keep the y before -ing, so you do not get two i’s in a row: carrying, studying, trying.

When the y stays

If the word ends in a vowel + y, keep the y: play → played, enjoy → enjoyment, employ → employer.

Rule 3: double the final consonant

Double the last consonant before a vowel suffix when the word:

1. has one syllable (or the stress is on the last syllable),
2. ends in one vowel followed by one consonant.

Do not double when…

• The word ends in two consonants: jump → jumping.
• The word has two vowels before the consonant: rain → raining.
• The suffix starts with a consonant: ship → shipment.
• The stress is not on the last syllable: visit → visited, open → opened.

Example

Why is it preferred but preference? In preferred, the stress stays on the last syllable of prefer, so we double the r. In preference, the stress moves to the first syllable, so we do not. Saying the word aloud helps you hear the difference.

Rule 4: just add it

For most other words, simply add the suffix with no changes: help → helpful, quick → quickly, kind → kindness.

A tricky -ly pair

Notice careful → carefully: the base already ends in l, so adding -ly gives two l’s. The same happens with real → really and final → finally.

When in doubt

English spelling has exceptions, so if a word looks strange after you add a suffix, check a dictionary or spell checker. Over time, the rules become automatic.

Key takeaways

• Drop a silent e before a vowel suffix, but keep it before a consonant suffix.
• Change consonant + y to i, except before -ing.
• Double the final consonant after a single short vowel in a stressed final syllable.
• Otherwise, just add the suffix, and say words aloud to check stress.

Practice

Add the suffix and spell the new word: 1. make + ing, 2. cry + ed, 3. swim + er, 4. enjoy + able, 5. hope + less, 6. admit + ed.

Answers: 1 making. 2 cried. 3 swimmer. 4 enjoyable. 5 hopeless. 6 admitted (stress on mit).