Prefixes and Suffixes (Your Complete Guide with PDF)

Increase your English vocabulary with the Root Word technique using prefixes and suffixes. I use this technique with my private students here in Japan. (And they love it!)

Prefixes and Suffixes are single letters or a group of letters added to the beginning or the end of a word to make a new word.
believe + Suffix ABLE = believable
believable + Prefix UN = unbelievable
*A prefix can also be a word, number, or letter. It may be separated by a hyphen. (-)
4-day work week.

In this post, you will learn an easy way to increase your English vocabulary. Keep reading.

What are Prefixes and Suffixes?

Prefixes and suffixes are important pieces of English grammar that can help you increase your vocabulary. You can combine prefixes and suffixes with words you already know to make new words. A Prefix is a letter or group of letters that go in front of a word and a Suffix goes at the end of a word.

Prefix un- + happy = unhappy
Prefix re- + do = redo
Prefix self- + employed = self-employed
happy + Suffix -ness = happiness
stable + Suffix -ize = stabilize
education + Suffix -al = educational

Increase English vocabulary with Prefixes and Suffixes

We will add prefixes and suffixes to words we may already know to make new words. I call this the ROOT word technique.

This is also something I use to learn Japanese vocabulary. I’m sure it can help you understand and use English too.

Let me share a real story to explain how we can use the root word technique to easily understand more English words.

Example Story – “What is a sweetener?”

Increase English vocabulary
Sweetener - two suffixes

I like to cook, and while I was looking at some new recipes, I saw a sweetener called “stevia” that was becoming common in North America. (This story is from 2008.) I did some research and I found that it has been used in Canada and America recently, but it has been used in Japan for more than 30 years! When I asked my students if they have heard about stevia we talked about sweeteners

Sweetener became the perfect word to introduce this technique because the word sweet is an easy and common word that everyone already understands.

Root word technique

A root word is the base (root) of a new word. When the root word is one that we already understand, it can help us learn the meaning of the new word. 

The root word of sweetener is sweet.

We know the meaning of the adjective sweet already, it describes a taste. 

“Sugar and honey are sweet.”

Oxford Advanced Learner’s Dictionary sweet adjective

Sweet can also be used as a noun (usually, a plural noun sweets) to mean candy. 

“My dentist said I eat too many sweets!” = I eat too much candy.

Oxford Advanced Learner’s Dictionary sweet noun

Sweeten is a verb that means: to make something sweet

“Many people use sugar to sweeten their coffee. Black coffee is too bitter for most people.”

(Bitter is the opposite of sweet, but we never use bitteren as a verb!)

Oxford Advanced Learner’s Dictionary sweeten verb

Learn more about the Suffix -EN at my blog post HERE

The Common Suffix -ER

So now we understand the verb sweeten, how about our new word sweetener? Let’s look at some other verbs that have “er” added at the end and see what they mean.

In baseball, the person who throws (pitches) the ball is called the pitcher. The person who hits (bats) the ball is the batter and the one who catches the ball is…? 

That’s right! The catcher

*The suffix -ER is not only for people. The machine that dries our hair is a hair dryer and the machine that mixes (blends) our food and drinks is a blender.

A verb followed by -er describes the person or thing that does that verb.

Here are some more examples of nouns ending in -er.

A floor wiper is a tool that you use to wipe your floor.

A pencil sharpener makes your pencils sharp. (It sharpens your pencils)

A container contains (holds) something. Tupperware is a well-known company in North America that makes plastic containers.

What do you think a sweetener does? It makes things taste SWEET.

When we use the noun sweetener we are most often talking about one that has fewer calories than sugar. An artificial (not natural) sweetener. 

More examples of words made from the root word SWEET.

Lollipops are sweet.

Donuts are sweeter than pie.

Cake is the sweetest.

I like to sweeten my cakes with honey instead of sugar.

Can I get some non-calorie sweetener for my coffee?

Too many sweets are bad for your teeth.

Maple syrup adds some sweetness to my pancakes.

Learn more about the Suffix -NESS at my blog post HERE

Advanced root word practice

Summer in Tokyo is very humid. I can make my apartment cooler by using the air conditioner.

[We can see now that an air conditioner is a machine that changes the condition of the air.]

Another machine that I like to use is called a dehumidifier.

A dehumidifier helps cool the air and I think it feels more comfortable than an air conditioner. Let’s use our root word practice on the word dehumidifier.

Increase English vocabulary 

Humid is an adjective that means – (of the air or climate) warm and slightly wet

“Summer in Tokyo is very humid.”

Humid is our root word. What about the other parts of the word?

There are 3 parts added to our root word.

We know what the suffix –ER means already. A verb followed by -er is the name of the person or thing that does that verb. What is the verb part of our word?

humidify verb to make dry air wetter (to add water to dry air)

Suffix -IFY

The suffix –IFY can mean “to make, cause to be” causing a word to become a verb.

  • To make something pure we can purify it.
  • To make something clear we want to clarify it.

Winter in Tokyo is much cooler than summer. A cold dry wind comes from the North, making the air dry. In the winter people in Tokyo may use a humidifier to make the air in their house or apartment more comfortable.

*Note that the suffix –IFY changes to –IFI when it is followed by the letter E.

A humidifier is a machine that adds moisture (water) to the air.

What about a dehumidifier? A dehumidifier is a humidifier with the prefix DE– in front.

Prefix DE-

The prefix DE– is sometimes used to mean remove or separate.

In the winter airports have machines that spray warm water on airplanes to de-ice the wings. (Remove the ice from the wing of an airplane.)

Before you cook a fish, you should debone it. (Remove the bone.)

Can you guess what a dehumidifier does? It takes the water out of the air.

dehumidifier – noun – an electrical machine for removing water from the air

Tokyo weather is a common topic during my private lessons, so it’s a nice way to introduce the word dehumidifier and talk about root word practice to increase English vocabulary. Dehumidifier has a prefix and two suffixes so it’s perfect!

The Prefix DE- 110 Common Words (PDF-Definitions-Examples)

More Great Prefix and Suffix Posts

These are 3 of my most popular Prefix/Suffix posts:

The suffix ~NESS – Increase Your Vocabulary Fast (Free PDF)
Your #1 Guide to using Over and Under as Prefixes (free PDF)
The Prefix RE – 60 examples (Definitions, Free PDF, Video)

The link below will take you to a collection of all my helpful Prefix and Suffix blog posts. This list is updated with my newest posts so it is always complete.

World English Blog Prefix and Suffix Blog Posts – A complete list

Root Word Technique PDF

Get a free PDF worksheet by clicking the image below.

Below is one of my first videos. I edited a small part out and uploaded it again in 2017 but it is still the original “quality” from 2013. It’s helpful and fun 🙂

Discover more from World English Blog

Subscribe now to keep reading and get access to the full archive.

Continue reading

Scroll to Top