What’s the Difference Between the Suffixes -IZE and -ISE?

I was prepping a lesson for a student who will travel to England for a business trip. During my research, I noticed that verbs made from nouns or adjectives can be spelled with an -ize or an -ise at the end. What’s the difference? Is there a difference? This post will answer these questions.

The suffix -ize is preferred in America and the suffix -ise is used in England.
There is no difference in meaning between these two suffixes. Both are used to turn nouns and adjectives into verbs.

I had more questions.
1) Why are they different?
2) Which spelling is preferred in other English-speaking countries?
3) Is there any difference in pronunciation?
Keep reading for these answers.

What’s The Difference Between -IZE and -ISE?

I found many resources online that talk about the different ways to spell English words. In this blog post, I will be talking specifically about the suffixes -ize and -ise. This means I’m looking at vocabulary words with a clear root word that is changed into a verb by adding these suffixes.

I didn’t include any words that end with -ise that are not verbs, (likewise, sunrise) or that don’t have a clear root word that is easy to recognize. (exercise, surprise)

The word surprise was once spelled with a ‘Z’! The Surprize spelling was once as common as Surprise. (Now it is nonstandard)

Many verbs can be written correctly with either spelling, the main factor that will decide which spelling you use is where your work will be published. The suffix -ize is the spelling of choice in America and the suffix -ise is more common in England.

Six Examples

*Note – In England, both spellings are acceptable but in America -ize is standard. Source

Google Docs will correct the spelling for whatever country you have set in the software. If you are set for America it will correct to ‘Z.’ if you are set for England it will correct for ‘S.’

Why There Are Two Different Spellings For This Suffix?

I wondered why are there two different spellings for the suffix? I did a little more digging and here is what I found:

“In the 19th century, it became common in the United Kingdom (due to French influence) to use -ise also on words that had historically been spelled -ize.”


I also found this:

“The -ize ending is the older, “truer” version and closer to its Greek roots and preferred by some. But the -ise endings are more widely used in British English.”


Is this quote saying that the suffix -ize is the correct spelling? Not exactly.

It’s saying that this suffix came from the Greek suffix -ίζειν, which becomes –izein when Romanized

*Romanized = written in the Roman alphabet. Learn more -ize verbs here > How To Use The Suffix -ize (List, Definitions, 48 Examples) Worldenglishblog.com/how-to-use-the-suffix-ize/

This Greek suffix (spelled with a Z) is used to turn nouns into verbs.
The French suffix -ise is actually used to form abstract nouns.
This is why some people prefer the ‘Z.’ They feel this spelling is closer to the true origin of the suffix. 

How words, spelling, and grammar are used in a language is determined by many factors. The time period, important writers, books, and newspapers, and even the languages of neighboring countries have influenced English.

What Is The Origin of The Suffix -ize? (History and Development)

Which Countries Use Which Spelling?

I learned that the -ise is not only common in England.

-ise is also common in Ireland, India, Australia, and New Zealand. -ize remains, however, the spelling used by the influential Oxford University Press.”


I wondered about Canada, I was going to ask a Canadian but then I realized –  I’m a Canadian! I’ve lived in Japan since 2016 so rather than trust my memory (which seems to prefer -ize) I decided to do a little research. Here’s what I did – I looked through a news article on a Canadian national news website, CBC News. 

I went to cbc.ca and found a random news story. Thousands of international students still waiting on permits after Canadian school year begins
I opened this new story in my browser (Google Chrome) and pressed control F. (This is the ‘FIND’ feature of your web browser that lets you search for words located n the webpage you are visiting.)

I typed in ize. No hyphen (-) and I found the words prioritize, modernized, and centralized. *modernized and centralized are the past participles of the verbs modernize and centralize being used as adjectives.

Next, I typed in ise. Zero results.
It seems like my memory is correct, -ize is the preferred choice of Canadian spelling.

This post is part of a group of posts that take a look at the suffix -ize. Visit these other posts and do a deeper dive into this suffix.

How To Use The Suffix -ize (List, Definitions, 48 Examples)

What Is The Origin of The Suffix -ize? (History and Development)

Confusing Suffixes -ize and -ify (How and When to Use Them) 

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