Often I find that my ESL students need more practice on spelling rules and how to use them in practice. If you’re looking for simple ways to show your students on when to use c or k in words, you will love this post. So I find that making quick posters along with simple listening games like this bingo one makes a huge difference on their learning!
Previously I shared a C or K fun printable game board and my students also love that one!

C or K rule in spelling
The English language has many spelling rules, but one of the most important is the distinction between the letters “c” and “k”.
Understanding when to use each letter is key to improving your students’ writing and avoiding spelling errors.
In this blog post, we’ll take a closer look at the “c” and “k” spelling rule and when to use each letter.
First, let’s define the “c” and “k” spelling rule. The “c” spelling rule states that the letter “c” should be used before the letters “a”, “o”, and “u”.
On the other hand, the “k” spelling rule states that the letter “k” should be used before the letters “e”, “i”, and “y”.
This rule is easy to remember with the mnemonic “ca, co, cu” and “ke, ki, ky”.
Usually, with my ESL students I keep it simple with the rule poster below:

C and K phonics rule
Here are some examples of words that follow the “c” spelling rule:
- Car
- Cat
- Cut
And here are some examples of words that follow the “k” spelling rule:
- Kite
- Kit
- Knee
It’s important to note that this rule is not absolute and there are exceptions.
For example, the word “carbon” uses the letter “c” before the letter “a”, but the word “knight” uses the letter “k” before the letter “i”.
This bingo game (found at the end of this post) is a great way to reinforce this rule and work on sounds too!

There are exceptions to the rule and I don’t go into too much details with my ESL students because it can get confusing!
However, I do say that some words are exceptions and sometimes we need to memorise these and know them by sight.
Another exception to the rule is when the word is a proper noun, such as the name “Caesar” or the country “Czech Republic”. In these cases, the spelling is not determined by the “c” or “k” rule, but by the correct spelling of the proper noun.
In summary, the “c” or “k” spelling rule is a helpful guideline for determining the correct spelling of words in English.
However, there are exceptions to the rule, so it’s important to encourage students to always consult a dictionary if they’re unsure.
More ESL phonics resources:
- S Phonics Worksheets Hands-on Fun Puzzles for Kids
- Short U Phonics Printables and Games
- How to teach letter sounds to struggling students [Free Downloads and Ideas]
- 5 Classic ESL Word Games Your Students Will Love
When to Use C or K Game and Poster
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