10 Most Common Grammar Mistakes That ESL Students Make (And How to Fix Them)

Have you ever written an English sentence, felt confident about it, and then discovered it was completely wrong? You’re not alone. Even advanced English learners stumble over the same grammar traps again and again.

The truth is, English grammar can be incredibly frustrating. Rules have exceptions. Exceptions have exceptions. And sometimes, what sounds perfectly logical in your native language creates confusion when translated into English.

After years of teaching English to students from dozens of countries, I’ve noticed something interesting: the same mistakes keep popping up, regardless of whether someone speaks Spanish, Mandarin, Arabic, or Russian. These errors aren’t signs of laziness or lack of intelligence. They’re simply the natural result of learning a language with quirky rules and inconsistent patterns.

Today, we’re going to tackle the ten grammar mistakes I see most often in my classroom. More importantly, I’ll show you practical ways to fix them for good.

1. Mixing Up “Its” and “It’s”

This mistake drives even native speakers crazy, so don’t feel bad if you’ve struggled with it.

The Problem: Students constantly confuse these two words because they look almost identical.

Here’s the fix: Remember this simple rule—”it’s” always means “it is” or “it has.” That apostrophe shows something is missing. “Its” (without the apostrophe) shows possession, like “his” or “her.”

Try this mental trick: whenever you write “it’s,” say the full phrase in your head. Does “it is” or “it has” make sense? If not, use “its.”

Wrong: The dog wagged it’s tail.
Right: The dog wagged its tail.

Wrong: Its raining outside.
Right: It’s raining outside.

Practice this until it becomes automatic. Your brain will eventually stop second-guessing itself.

2. Forgetting Articles (A, An, The)

If your native language doesn’t use articles, this mistake probably haunts your writing.

The Problem: Many languages don’t have words like “a,” “an,” or “the,” so ESL students often skip them entirely or use them incorrectly.

Here’s the fix: Think about whether you’re talking about something specific or something general. Use “the” when both you and your reader know exactly what you’re referring to. Use “a” or “an” when you’re mentioning something for the first time or talking about any example of something.

Also, remember that “an” comes before vowel sounds (not just vowel letters). Say the word out loud—if it starts with a vowel sound, use “an.”

Wrong: I need to buy car.
Right: I need to buy a car.

Wrong: Can you close door?
Right: Can you close the door?

Wrong: She is a honest person.
Right: She is an honest person. (The “h” is silent, so it starts with a vowel sound)

Start paying attention to articles when you read English. Notice when writers use them and when they don’t. Patterns will emerge.

3. Confusing “There,” “Their,” and “They’re”

These three words sound identical but mean completely different things.

The Problem: Because they’re pronounced the same way, students mix them up constantly in writing.

Here’s the fix: Break them down by function:

• “They’re” = they are (another contraction with an apostrophe showing missing letters)
• “Their” = shows possession (belongs to them)
• “There” = refers to a place or used in phrases like “there is”

Wrong: Their going to the store over they’re.
Right: They’re going to the store over there.

Wrong: The students forgot there books.
Right: The students forgot their books.

Create flashcards or write these in different colored pens. The visual difference will help your brain sort them out.

4. Using Double Negatives

In some languages, using two negative words makes the negative meaning stronger. English works differently.

The Problem: Students say things like “I don’t have no money” or “She doesn’t know nothing,” which actually creates confusion or sounds incorrect.

Here’s the fix: In standard English, two negatives cancel each other out (like in math). Use only one negative word per clause.

Wrong: I don’t want nothing.
Right: I don’t want anything.
OR: I want nothing.

Wrong: He doesn’t never call me.
Right: He doesn’t ever call me.
OR: He never calls me.

Watch for negative words like “no,” “not,” “never,” “nobody,” “nothing,” and “nowhere.” If you spot two in the same part of a sentence, remove one.

5. Misplacing Apostrophes in Plurals

Here’s a mistake that makes writing look unprofessional instantly.

The Problem: Students add apostrophes to plural words, writing things like “apple’s” when they mean “apples.”

Here’s the fix: Apostrophes show possession (ownership) or missing letters in contractions. They don’t make words plural. To make most English words plural, just add “s” or “es.”

Wrong: I bought three banana’s at the store.
Right: I bought three bananas at the store.

Wrong: The teacher’s are having a meeting. (unless you mean one teacher’s something)
Right: The teachers are having a meeting.

Right (possession): The teacher’s desk is messy. (the desk belonging to one teacher)
Right (plural possession): The teachers’ lounge needs cleaning. (the lounge belonging to multiple teachers)

Here’s a quick test: if you’re just talking about more than one thing, no apostrophe needed.

6. Subject-Verb Agreement Errors

This mistake shows up everywhere, even in advanced students’ writing.

The Problem: The subject and verb don’t match in number. Students write “He go” instead of “He goes” or “They was” instead of “They were.”

Here’s the fix: Pay special attention to third-person singular subjects (he, she, it) in the present tense. These almost always need an “s” on the verb. Plural subjects don’t.

Also, remember that some subjects that sound plural are actually singular (like “everyone,” “somebody,” or “the team”).

Wrong: She walk to school every day.
Right: She walks to school every day.

Wrong: Everyone were excited about the trip.
Right: Everyone was excited about the trip.

Wrong: The information are available online.
Right: The information is available online.

Read your sentences out loud. Your ear will often catch these mistakes even when your eyes miss them.

7. Overusing “Very” and “Really”

While not technically a grammar error, this habit weakens your writing significantly.

The Problem: ESL students (and native speakers too) rely on “very” and “really” to intensify meaning, creating boring, repetitive sentences.

Here’s the fix: Replace “very + adjective” combinations with stronger, more precise words.

Weak: The movie was very scary.
Better: The movie was terrifying.

Weak: I’m very tired.
Better: I’m exhausted.

Weak: The test was really hard.
Better: The test was challenging.

Build a personal list of strong adjectives and verbs. When you catch yourself writing “very” or “really,” pause and think of a more powerful word.

8. Confusing “Less” and “Fewer”

This distinction trips up learners constantly, and honestly, many native speakers get it wrong too.

The Problem: Students use these words interchangeably, but they follow specific rules based on whether something can be counted.

Here’s the fix: Use “fewer” for things you can count individually (countable nouns). Use “less” for things you can’t count or for abstract concepts (uncountable nouns).

Wrong: There are less students in class today.
Right: There are fewer students in class today. (you can count students)

Wrong: I need to spend fewer money on coffee.
Right: I need to spend less money on coffee. (you don’t count individual moneys)

Wrong: This recipe needs fewer sugar.
Right: This recipe needs less sugar. (sugar isn’t counted individually)

Ask yourself: can I count this one by one? If yes, use “fewer.”

9. Misusing Prepositions (In, On, At)

Prepositions might be the hardest part of English. They often seem random and illogical.

The Problem: Students say “in the morning” but “at night,” “on Monday” but “in January.” These small words follow patterns that don’t always translate from other languages.

Here’s the fix: Learn the most common patterns for time and place:

Time:

• Use “at” for specific times: at 3 PM, at midnight, at noon
• Use “on” for days and dates: on Monday, on June 5th, on weekends
• Use “in” for months, years, and longer periods: in March, in 2024, in the morning

Place:

• Use “at” for specific locations: at the store, at school, at home
• Use “on” for surfaces: on the table, on the wall, on the second floor
• Use “in” for enclosed spaces: in the room, in the car, in Paris

Wrong: I’ll meet you in 3 PM on the park.
Right: I’ll meet you at 3 PM in the park.

Unfortunately, you’ll need to memorize some of these. Create visual charts or use color-coding to help the patterns stick.

10. Mixing Up “Make” and “Do”

These two verbs cause endless confusion because many languages use just one word for both concepts.

The Problem: Students aren’t sure whether to say “make homework” or “do homework,” “make a decision” or “do a decision.”

Here’s the fix: Generally, use “make” when you’re creating or producing something. Use “do” for activities, tasks, or actions.

Common “make” phrases:

• make a mistake
• make a decision
• make progress
• make money
• make breakfast
• make a phone call

Common “do” phrases:

• do homework
• do the dishes
• do exercise
• do business
• do your best
• do someone a favor

Wrong: I need to make my homework before dinner.
Right: I need to do my homework before dinner.

Wrong: She did a big mistake on the test.
Right: She made a big mistake on the test.

Create two lists in your notebook and add to them whenever you learn a new phrase. Eventually, these combinations will feel natural.

Moving Forward

Grammar mistakes aren’t permanent problems. They’re simply habits that can be changed with awareness and practice.

Here’s what I recommend: pick just one or two mistakes from this list that you know you make regularly. Focus on those for the next few weeks. Check your writing specifically for those errors. Ask friends or teachers to point them out when they notice them.

Don’t try to fix everything at once. That approach leads to frustration and burnout. Master one mistake at a time, and before you know it, your English will sound smoother and more natural.

Remember, even native speakers make these mistakes. The difference is that you’re actively working to improve, which puts you ahead of the game.

Frequently Asked Questions

How long does it take to break these grammar habits?

It varies by person and by mistake, but with focused practice, most students see improvement within 2-3 weeks for a single error type. Some mistakes (like article usage) might take several months to master completely.

Should I worry about grammar when speaking, or just when writing?

Start by focusing on writing, where you have time to think and self-correct. As the correct forms become automatic in writing, they’ll naturally transfer to your speaking.

What if my native language doesn’t have articles—will I ever master them?

Yes, absolutely. It takes longer and requires more conscious effort, but thousands of learners from article-free languages have mastered English articles. Consistent exposure and practice are key.

Are these mistakes really that important, or can people understand me anyway?

People will usually understand you despite these errors, but fixing them makes your English sound more professional and polished. In academic and business settings, these details matter more.

What’s the best way to practice fixing these mistakes?

Keep a grammar journal where you write example sentences using the correct forms. Review it regularly. Also, read extensively—seeing correct grammar in context is one of the most effective learning tools.