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Ten of the Most Common Grammar Mistakes and How To Easily Avoid Them

Updated: Feb 8, 2022

picture of a lady writing, with text which says ten of the most common grammar mistakes and how to easily avoid themt

Learning grammar — in any language — is not an easy undertaking! Here is a list of the 10 most common grammar mistakes that students and adults alike make every day! Learn how to avoid them and improve your child's literacy skills.

1. The most common grammatical mistake - Their, There and They’re

a quote which says the most common grammatical mistake - their, there and they're

Mixing up Their, There and They’re is one of the most common grammatical errors, even for adults. I tell my students it is easy to eliminate one of these by remembering when not to use it.

They’re is a contraction meaning they are. When writing and using the word There/Their/They’re we can substitute they are to see if it makes sense.

“ When we go There/Their/They’re it will be fun “

When we go they are it will be fun.

This doesn’t make sense so we can immediately cross they’re to use here.

“They’re going to the party. “

This one makes sense.

We use (their) when we are talking about possessiveness or when a person owns something.

For example - It was their jacket in the lost property bin.

Learning to use (there) for places is a good rule to remember but keep in mind the would there can also be used as a pronoun.

“There is a car outside.”

There can also be used as an interjection/exclamation:

“There! Are you happy now?”

Since there has more different kinds of uses than they’re and their, we like to teach the elimination method by first testing to see if they’re or their options fit.

2. Another common grammar mistake is Your vs You’re

This one is another common grammar mistake that again adults also make too! Learning English isn’t easy even when English is your mother tongue.

There’s an easy way to remember when to use your or you’re. Remember that you’re is a contraction for “you are.” Substitute you are to see if it works! For example:

“Mum said to finish eating you are dinner before watching TV.”

a watercolour background with text that says there is an easy way to remember when to use your or you're. Remembr that you're is a contraction for you  are. Substitute you are to see if it works!

This sentence doesn’t make much sense when we substitute you are – meaning your is the only remaining option. Just like their, your is also possessive – in the previous example, the dinner belongs to the person being told to finish eating it!

“Mum said to finish eating your dinner before watching TV.”

3. Apostrophe Usage

Apostrophes are used to show possession i.e who owns something. Although we need to remember that we do not use an apostrophe after a possessive pronoun such as my, mine, our, ours, his, hers, its, their, or theirs.

For example:

  • Incorrect: “My mothers book is next to the lamp.”

  • Correct: “My mother's book is next to the lamp.”

apostrophes are used to show who owns something

Apostrophes are also used for contractions. This leads us to number 4.

4. Missing Apostrophes Out of Contractions

A contraction is a shortened form of a word (or group of words) that omits certain letters or sounds. In most contractions, an apostrophe represents the missing letters. Some examples of contractions are:

He would=He’d. I have=I’ve. They are=They’re. You cannot=You can’t.

Children often miss out the apostrophe when using contractions and see these as a new word of their own. They often don’t understand that these represent two or more words.

5. Using Capitals and Full stops

The bugbear of teachers everywhere is when students don’t use capital letters and full stops. If you want your children to improve their writing, helping them to consistently use capital letters and full stops will go a long way! When teachers mark students’ writing according to the Australian curriculum guidelines, marks are taken off for not using capital letters and full stops even in the very low grades.

a wter colour background with a quote that says help your children improve their writing by reminding them to use capital letters and fullstops.

So when should we use capital letters? At the beginning of a sentence and for proper nouns. A proper noun is the name of a person, place, organisation, or trademark. I.e Brad Pitt, Australia, Nike, and McDonald’s.

We use full stops at the end of every sentence unless we are another type of punctuation such as a question mark or exclamation mark.

6. Run-on Sentences

A really common grammatical error that children make when learning to write, is using run-on sentences. A run-on sentence is one giant sentence that never ends and should really be 2 to 3 or even more stand-alone sentences. An example would be:

“The giant dog went under a gap on the fence then he ran down the street happily with his tongue hanging out and then trotted down to the park where he watched the children


text which says avoid run on sentences by asking your children to read their writing back - see if they run out of breath. If yes it's too long.

Encouraging your children to read back their writing will help to identify sentences that are too long.

7. Not using plurals correctly

This is one of the common grammar mistakes for ESL students - not using plurals correctly. Many students whose first language is not English, have difficulty with plurals. This is because other languages don’t use plurals in the same way as English.

“ Look at all the star.”

” Look at all the stars.”

picture of a text bubble which says many students whose first language is not english, have difficulty with plurals. This is because other languages don't use plurals in the same way.

8. Dialogue punctuation mistakes

So many students are confused about the rules that apply to writing dialogue or using speech marks.

These may be a few of the mistakes that your child has made in his or her writing:

“Jane go and pack your room! My mother shouted”.

A loud, “authoritative voice shouted. “Mark!”

John shouted proudly Wow! That’s good! Let’s go out and eat today!”

Speech Marks sometimes called Quotation marks, only go around the words that are being said.

9. When to use To, Too, or Two

It is easy to get to, too and two mixed up, it is one of the most common grammar mistakes. However, there is an easy rule to make sure you remember which one to use.

To, is the default word used in most occasions. Too is only used in two specific ways. The first meaning also and the second when defining something as extreme. For example;

“I am going to the shops too.”

“The spa is way too hot for me.”

The other two is simple - it is the number 2. We use the word two when writing numbers smaller than ten.

“I saw two dolphins in the water.”

10. The Difference between "Wether," "Weather," and "Whether"

Yes, wether is a real word! It is easy to confuse wether, weather, and whether. The first Wether, apart from being a common misspelling of weather or whether. "Wether" is a castrated ram (male sheep). For example:

My wether still has an eye for the lady sheep.

The word weather refers to the climate outside for example:

Bring a jacket. We're expecting bad weather.

The last Whether is used similarly to the word if. For example:

I wonder whether it will rain.


Hopefully, this article has helped out identify some of the common grammar mistakes that students make. By improving a student's grammar skills they will naturally improve their reading and writing too.

To help your child improve their grammar and literacy skills book in for tutoring with Wise Owl Tuition here.

What are some of the common grammar mistakes that you see? Comment below

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