30 Common Grammar Mistakes to Avoid in English Writing and Speaking

Grammar plays a very important role in clear and confident English communication. Even learners with good vocabulary often make small grammar mistakes that can change the meaning of a sentence or make it sound incorrect.

These errors usually happen because of confusion between similar structures, direct translation from the mother tongue, or lack of practice.

In this post, you will learn 30 common grammar mistakes to avoid in everyday English. Each mistake is explained in a simple and easy way, making it perfect for students, competitive exam aspirants, and ESL learners.

By understanding and correcting these common errors, you can improve your spoken and written English, sound more natural, and communicate your ideas more clearly.

Your vs. You’re

One of the most common mistakes is confusing “your” and “you’re.”

• Your: Possessive adjective (Your car is red.)
• You’re: Contraction of “you are” (You’re going to the party.)

Tip: If you can replace the word with “you are,” use “you’re.” Otherwise, use “your.”

Its vs. It’s

Another frequent error involves “its” and “it’s.”

• Its: Possessive pronoun (The dog wagged its tail.)
• It’s: Contraction of “it is” or “it has” (It’s raining outside.)

Tip: If you can replace the word with “it is” or “it has,” use “it’s.” Otherwise, use “its.”

There, Their, and They’re

These homophones often cause confusion:

• There: Indicates location (Put the book over there.)
• Their: Possessive pronoun (Their house is beautiful.)
• They’re: Contraction of “they are” (They’re going to the movies.)

Tip: Replace “they’re” with “they are” to check if it makes sense. Use “their” for possession and “there” for location.

To, Too, and Two

Another set of commonly confused words:

• To: Preposition indicating direction or recipient (I’m going to the store.)
• Too: Means “also” or “excessively” (I want to go too. / It’s too hot.)
• Two: The number 2 (I have two cats.)

Tip: Remember that “too” has an extra “o” like “also,” and “two” has a “w” like other number words (twelve, twenty).

Affect vs. Effect

These words are often misused:

• Affect: Usually a verb meaning to influence (The rain affected our plans.)
• Effect: Usually a noun meaning result or consequence (The effect of the rain was cancelation.)

Tip: Remember “RAVEN” – Remember Affect is a Verb, Effect is a Noun.

Who vs. Whom

Many writers struggle with when to use “who” or “whom”:

• Who: Subject pronoun (Who wants ice cream?)
• Whom: Object pronoun (To whom should I address the letter?)

Tip: If you can replace the word with “he” or “she,” use “who.” If you can replace it with “him” or “her,” use “whom.”

Lay vs. Lie

These verbs are frequently confused:

• Lay: Requires a direct object (Lay the book on the table.)
• Lie: Doesn’t require a direct object (I’m going to lie down for a nap.)

Tip: “Lay” means to place something, while “lie” means to recline.

i.e. vs. e.g.

These Latin abbreviations are often misused:

• i.e.: Means “that is” or “in other words” (I love citrus fruits, i.e., oranges and lemons.)
• e.g.: Means “for example” (I love citrus fruits, e.g., oranges and lemons.)

Tip: Use “i.e.” to clarify and “e.g.” to give examples.

Fewer vs. Less

Another common mistake involves “fewer” and “less”:

• Fewer: Use with countable nouns (I have fewer apples than you.)
• Less: Use with uncountable nouns (I have less money than you.)

Tip: If you can count it, use “fewer.” If you can’t count it, use “less.”

Then vs. Than

These words are sometimes confused in writing:

• Then: Relates to time (We’ll go to the store, then to the park.)
• Than: Used for comparisons (I’m taller than my brother.)

Tip: “Then” is about time; “than” is about comparisons.

Could of, Would of, Should of

This is a common error based on the pronunciation of contractions:

Incorrect: I could of gone to the party. Correct: I could have gone to the party. (or I could’ve gone to the party.)

Tip: Remember, it’s always “have,” never “of” in these phrases.

Me, Myself, and I

Many people struggle with when to use these pronouns:

• Me: Object pronoun (Give the book to me.)
• I: Subject pronoun (I went to the store.)
• Myself: Reflexive pronoun (I hurt myself.)

Tip: Remove the other person from the sentence to check which pronoun sounds correct.

Apostrophes for Plurals

Using apostrophes to make words plural is a common mistake:

Incorrect: I bought apple’s at the store.

 Correct: I bought apples at the store.

Tip: Use apostrophes for possession or contractions, not for plurals.

Subject-Verb Agreement

Ensuring subjects and verbs agree in number is crucial:

Incorrect: The group of students were noisy.

Correct: The group of students was noisy.

Tip: Identify the true subject and make sure the verb agrees with it.

Dangling Modifiers

These can create ambiguity or unintentionally humorous sentences:

Incorrect: Walking down the street, the trees were beautiful.

Correct: Walking down the street, I saw that the trees were beautiful.

Tip: Make sure the modifier is clearly connected to the subject it’s describing.

Run-on Sentences

Run-on sentences occur when two independent clauses are joined incorrectly:

Incorrect: It was raining I stayed home.

Correct: It was raining, so I stayed home.

Tip: Use proper punctuation or conjunctions to join independent clauses.

Comma Splices

Similar to run-on sentences, comma splices occur when a comma alone is used to join two independent clauses:

Incorrect: I love coffee, it keeps me awake.

Correct: I love coffee; it keeps me awake. (or) I love coffee because it keeps me awake.

Tip: Use a semicolon, period, or conjunction to correct comma splices.

Misplaced Modifiers

These can change the meaning of a sentence:

Incorrect: I only eat vegetables.

Correct: I eat only vegetables.

Tip: Place modifiers as close as possible to the words they’re modifying.

Double Negatives

Using two negative words in a sentence can create confusion:

Incorrect: I don’t have no money.

Correct: I don’t have any money. (or) I have no money.

Tip: Use only one negative word to express a negative idea.

Irregular Verbs

Some verbs don’t follow regular conjugation patterns:

Incorrect: I goed to the store.

Correct: I went to the store.

Tip: Memorize common irregular verbs and their conjugations.

Pronoun Agreement

Pronouns should agree in number with their antecedents:

Incorrect: Each student should bring their book.

Correct: Each student should bring his or her book. (or) All students should bring their books.

Tip: Ensure the pronoun matches the number (singular or plural) of its antecedent.

Parallelism

Parallel structure is important in lists and comparisons:

Incorrect: I like swimming, to hike, and riding bikes.

Correct: I like swimming, hiking, and riding bikes.

Tip: Use consistent grammatical forms in lists and comparisons.

Split Infinitives

While not always incorrect, split infinitives can sometimes be awkward:

Potentially awkward: To boldly go where no one has gone before.

Alternative: To go boldly where no one has gone before.

Tip: While split infinitives are sometimes acceptable, consider if the sentence flows better without splitting the infinitive.

Ending Sentences with Prepositions

This “rule” is often overstated, but it’s worth considering:

Informal: Where are you at?

More formal: Where are you?

Tip: While it’s not always wrong to end a sentence with a preposition, consider if the preposition is necessary.

Between vs. Among

These prepositions are sometimes confused:

• Between: Use for two items (The prize was divided between John and Mary.)
• Among: Use for three or more items (The prize was divided among the five finalists.)

Tip: “Between” for two, “among” for three or more.

Redundancy

Avoid using unnecessary words that repeat information:

Redundant: Please RSVP by tomorrow at 5 p.m. in the evening.

Concise: Please RSVP by tomorrow at 5 p.m.

Tip: Review your writing to eliminate unnecessary repetition.

Use of Quotation Marks

Misuse of quotation marks can change the meaning of a sentence:

Incorrect: The “fresh” fish wasn’t very good.

Correct: The fresh fish wasn’t very good.

Tip: Use quotation marks for direct quotes, titles of short works, or to indicate irony, not for emphasis.

Passive Voice Overuse

While not always incorrect, overuse of passive voice can make writing weak:

Passive: The ball was thrown by John.

Active: John threw the ball.

Tip: Use active voice most of the time for clearer, more direct writing.

Misuse of Semicolons

Semicolons are often misused or overused:

Incorrect: I love grammar; it’s fun, and exciting.

Correct: I love grammar; it’s fun and exciting.

Tip: Use semicolons to join related independent clauses or in complex lists.

Compound Words

Knowing when to use hyphens in compound words can be tricky:

Incorrect: I have a six year old daughter.

Correct: I have a six-year-old daughter.

Tip: When compound adjectives come before a noun, they’re usually hyphenated.

Final Thoughts

Learning these basic grammar rules will really help you become a better writer.

Just remember, language is always changing, so some rules might be different in the future.

The important thing is to make sure your writing is clear and makes sense.

You may also like these English learning articles:

• When to Use Semicolons vs. Commas in English Grammar
• Indicative, Imperative, Subjunctive Mood Explained with Examples
• Subordinating Conjunctions: A Simple Guide with Examples
• Prepositions of Time in English: Basic Rules and Examples
• Prepositions of Movement in English: Easy Guide with Examples