5 Common Grammar Mistakes to Avoid

February 27, 2026 ESL Experts 12 min read

Even advanced English learners make common grammar mistakes that undermine their credibility and clarity. These errors are so frequent that native speakers have become numb to them - but they still notice! This guide reveals the top mistakes holding back your English and provides practical strategies to eliminate them from your writing and speech.

💡 Key Insight: Fixing just 5 common mistakes can immediately improve how people perceive your English proficiency. These errors are easy to fix once you understand the rules.

1. Their vs. There vs. They're

This is perhaps the most common mistake in English. All three words sound identical when spoken (homophones), but they have completely different meanings and uses.

  • Their - Possessive pronoun showing something belongs to or is associated with a group: "Their house is beautiful." "The students submitted their assignments."
  • There - Indicates existence, location, or direction: "The book is over there." "There are five people in the room."
  • They're - Contraction (combination) of "they are": "They're coming to the party." "They're going to be late."
❌ Their going to there house to get there keys.
(Incorrect - mixes all three forms incorrectly)
✅ They're going to their house to get their keys.
(Correct - uses "They're" for contraction, "their" for possession twice)

2. Your vs. You're

Similar to the "their/there/they're" confusion, these two homophones are frequently mixed up because they sound identical.

  • Your - Possessive pronoun showing something belongs to or is associated with the person you're addressing: "Your presentation was excellent." "Is this your laptop?"
  • You're - Contraction of "you are": "You're doing great!" "You're going to love this movie."
❌ Your going to improve you're English with practice.
(Incorrect - "Your going" doesn't make sense; should be "You're going")
✅ You're going to improve your English with practice.
(Correct - "You're" = you are; "your" = possession)
💡 Quick Tip: If you can replace the word with "you are" or "they are," use the contraction (you're/they're). Otherwise, use the possessive (your/their).

3. Subject-Verb Agreement

The subject and verb in a sentence must agree in number. If the subject is singular, the verb must be singular. If the subject is plural, the verb must be plural. This becomes tricky with collective nouns and phrases.

  • Singular subject: "The team is playing well." (NOT "are playing")
  • Plural subject: "The players are performing excellently." (NOT "is performing")
  • Collective noun: "The committee has made its decision." (Treated as singular in formal English)
❌ The group of students are going to the museum.
(Incorrect - "group" is singular, so use "is")
✅ The group of students is going to the museum.
(Correct - "group" is the subject, which is singular)

4. Confusing "Its" vs. "It's"

Another homophone problem: these two words sound identical but have different meanings and uses.

  • Its - Possessive pronoun showing something belongs to or is associated with an object or animal: "The cat licked its paws." "The company released its annual report."
  • It's - Contraction of "it is": "It's a beautiful day." "It's important to practice regularly."
❌ It's important that the company maintains it's reputation.
(Incorrect - second "it's" should be "its")
✅ It's important that the company maintains its reputation.
(Correct - "It's" = it is; "its" = possession)

5. Misplaced Modifiers

Modifiers are words or phrases that describe other words. When a modifier is placed too far from the word it describes, it can create confusing or unintentionally funny sentences.

  • Dangling modifier: A descriptive phrase without a clear subject: "Walking down the street, the buildings were tall." (Who is walking? Buildings aren't walking!)
  • Misplaced modifier: The modifier is too far from the word it describes: "I saw the dog running in the park with my binoculars." (Were the binoculars running in the park?)
❌ Running late to the meeting, the traffic was terrible.
(Who was running late? The traffic wasn't!)
✅ Running late to the meeting, I got stuck in terrible traffic.
(Clear that "I" am the subject of the modifier "running late")

Bonus: 5 More Common Mistakes

6. Double Negatives

❌ "I don't want no problems" (This actually means you DO want problems!)
✅ "I don't want any problems"

7. Comma Splice

❌ "She loves writing, it's her passion."
✅ "She loves writing; it's her passion." OR "She loves writing because it's her passion."

8. Incorrect Pronoun Case

❌ "Between you and I, this is a problem."
✅ "Between you and me, this is a problem." (Use objective case after prepositions)

9. Who vs. Whom

❌ "Whom did you talk to?" (For some speakers)
✅ "Who did you talk to?" (Modern English tends to use "who" in most contexts)

10. Sentence Fragments

❌ "Although she studied hard. She failed the test."
✅ "Although she studied hard, she failed the test." (Complete sentence)

Quick Fix Checklist

✅ Before submitting any important writing, check for:
  • Their/There/They're confusion
  • Your/You're confusion
  • Its/It's confusion
  • Subject-verb agreement
  • Misplaced modifiers
  • Double negatives
  • Comma splices

Key Takeaways

✅ Homophones (your/you're, their/there/they're) are the most common source of grammar errors
✅ Subjects and verbs must agree in number
✅ Modifiers must be placed directly next to the words they describe
✅ Proofreading and using online grammar tools helps catch mistakes
✅ Many native speakers make these mistakes too - awareness is the first step
✅ Consistent practice with these corrections improves your written English dramatically

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Grammar Tips

5 Common Grammar Mistakes to Avoid

Even advanced English learners make these errors. Learn how to fix them!

December 2024 7 min read

1. Their vs. There vs. They're

This is perhaps the most common mistake in English. Here's the difference:

  • Their - Possessive pronoun: "Their house is beautiful."
  • There - Location or existence: "The book is over there."
  • They're - Contraction of "they are": "They're coming to the party."

2. Your vs. You're

Another common confusion between possessive and contraction:

  • Your - Possessive: "Is this your book?"
  • You're - Contraction of "you are": "You're doing great!"

3. Its vs. It's

This one trips up even native speakers:

  • Its - Possessive: "The cat licked its paw."
  • It's - Contraction of "it is" or "it has": "It's raining outside."

4. Affect vs. Effect

A classic vocabulary confusion:

  • Affect - Verb: "The weather affects my mood."
  • Effect - Noun: "The effect of the medicine was immediate."

Tip: Affect is the Action (verb), Effect is the End result (noun).

5. Subject-Verb Agreement

Make sure your subject and verb agree in number:

  • ❌ "The group of students are waiting."
  • ✅ "The group of students is waiting."
  • ❌ "Everyone have their own opinion."
  • ✅ "Everyone has their own opinion."

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