Suffixing: The Doubling Rule

Oct 15, 2021 | Posted by Jennifer

In the first blog post dedicated to suffixing, I addressed the dropping rule. This rule essentially states that one should drop the final nonsyllabic (silent) e before applying a vowel suffix. There are two other suffix rules I’d like to describe: the doubling rule and the change rule. Today we will cover the former and will address the latter in a separate blog post. If you haven’t read the first post, which outlines the dropping rule, you may want to start there. Then jump back and read this post.

Like the dropping rule, the doubling rule applies to vowel suffixes only. Its name refers to the fact that the last letter in the base word is doubled and has three components, which can make it a little tricky to apply. They are as follows:

  1. The base word must end with a consonant-vowel-consonant.

  2. The suffix must be a vowel suffix.

  3. If the word has two syllables, the final syllable must be the one that is accented.

Let’s practice applying the rule by taking a few base words and seeing how it works. We’ll use the same suffix that we did in the dropping post: -ing. I will bold the doubled letter.

  • hop + ing = hopping

  • bat + ing = batting

  • star + ing = starring

  • stir + ing = stirring

  • compel (pel is accented) + ing = compelling

  • infer (fer is accented) + ing - inferring

Knowing your suffix rules makes not only spelling the word easier but also makes reading it much easier. Look at the first three words on the list: hopping, batting, and starring. Knowing whether the doubling or the drop rule was applied will help you to decode the correct word. Words that use the dropping rule only have one consonant at the end, and the base words have long vowels: hoping, bating, and staring.

There are a few exceptions to this rule. Don’t double the letters <x> or <w>. Following that logic, we find that fix becomes fixing, and row becomes rowing. Why is this? The letter <x> actually makes two consonant sounds in rapid succession: /k/ and /s/. With the letter <w> at the end of words, it functions together with the vowel to make a vowel team. Examples would include words such as drawing, stewing, and flowing.

Now that we’ve covered both the doubling and the dropping rules, how about playing a little game that I created? See how quickly you can apply the rule for the correct spelling. Share it with your students who are ready to learn these concepts too. Hopefully they will find it a fun way to test how solid they are with those two rules. Keep your eyes open for a future blog post that discusses the change rule.


Jennifer Mauser has always loved reading and writing and received a B.A. in English from the University of Kansas in 1991. Once she and her husband had children, they decided to homeschool, and she put all her training to use in the home. In addition to homeschooling her children, Jennifer teaches IEW classes out of her home, coaches budding writers via email, and tutors students who struggle with dyslexia.

Live Chat with IEW