15 Grammar Mistakes That Ruin Your Credibility


chima mmeje

Last month, my cousin sent me a message with the words “idk”. I was confused. I had seen it on several chat messages but I didn’t understand the words.

I asked her what it meant and she said: “I don’t know”.

I replied, “what do you mean you don’t know? You literally just sent me this message!”.

She typed “lol” with a laughing emoticon and said, “exactly. I don’t know”

It hit me. “idk” means “I don’t know.” Slangs and bad grammar are the new normal. Thanks to social media, people are too lazy to type complete sentences. The standard of spelling and grammar has taken a nose dive. Acronyms, random typos and “cool” memes are all over the internet.

Disruptive Communications conducted a UK study on factors that damage a consumer’s view of a brand. The study revealed that poor spelling and grammar mistakes were the primary reason for a damaged brand reputation.

Another survey by Global Lingo found that 59% of the respondents would not use a company that had spelling or grammar errors on their marketing materials or website content.

NYU Professor, Panos Ipeirotis conducted his own study. He noticed that demand for hotel rooms on TripAdvisor increased when the reviews were free of grammar and spelling mistakes. Similar to Amazon, where revenue increased after they fixed spelling errors in customer reviews.

Grammar and good spelling matter. You can’t afford to ignore grammar errors if you want your prospects to take you seriously.  Bad spelling affects your online credibility. It detracts from an amazing product.

Customers will doubt the credibility of your product if you don’t proofread your content. Investing in an editor or copywriter with editing skills is not a luxury. It’s a necessity.

Grammar Mistakes to Avoid in Copywriting

Defiantly – Definitely

This could either be a general confusion or the advent of predictive text. It is a common spelling mistake you should avoid. Stan Carey says that most people on Twitter use “defiantly” in place of “definitely”.

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  • James will defiantly leave the wine cooler behind.
  • I will defiantly visit the grocery store on Sunday.


  • I am definitely going to work tomorrow. I can’t afford another strike on my record.
  • John will definitely miss the train on Sunday. He hates waking up before 7 am.


“Effect” is commonly interchanged for “affect”.


  • Sheila’s death had an affect on my mental health (effect)
  • What is the affect of social media on the job market (effect)
  • The heat wave has effected productivity levels (affected)


  • The lack of funds affected our ability to provide free meals for the poor
  • Bad roads in Aba has a direct effect on tourism

The key is to remember that “effect” is used as a noun, resulting in something. While “affect” is used as a verb, when a factor is influenced.

Misusing There and Here

When writing a web copy, your subjects and verbs must agree. It helps to clarify your sentences.


  • Here’s lots of tools to make your life easier

The subject, “lots of tools” is plural and the verb “here’s” is singular. The sentence needs a plural verb for uniformity.


  • Here are tools to make your life easier.”

If you’re feeling confused, avoid these sentences in your writing altogether.  Sentences with “here are”, “there is” and “there are” are expletive constructions that serve a function but don’t have meaning.

Confusing “you’re” and “your”

The muddling of your and you’re is one of the oldest grammar mistakes.

Your is a possessive while You’re is a contraction.


  • You’re website is cluttered
  • You’re son beat me to the top score


  • Your girlfriend is attractive
  • Your dog is stubborn
  • You’re the best person for the job
  • You’re going to handle the BG project.

If the word “are” doesn’t belong in the sentence, don’t use it. There are similar errors. Such as the correct use of “They’re, There and Their”. “They’re” is also a contradiction of “they” and “are”. “Their” is a possessive.

For instance

There is something in front of the door

They’re looking for the payment vouchers

Their mum is a generous woman

They won’t ask Jack any questions without his attorney in the room.

Who and Whom

The misuse of “whom” is a frequent error in many conversations. It mostly happens when a phrase intervenes between the pronoun and its subject.


  • My mother told me to stay away from Jemima, whom according to her, is under the influence of drugs. (who)


  • Do you know who is in charge of the meal tickets?

Sentences that include “in my opinion”, “according to” and other related phrases are where the problems lie. Do not substitute “whom” for “who” when nothing is between it and its verb.

Its and It’s

Without Grammarly checking my content for errors, I would fall prey to this grammar mistake every time. This tiny apostrophe makes all the difference. “Its” is used for a possessive pronoun. “It’s” is used to contradict the term “it is”.

For instance

  • The school decides its valedictorian.
  • It’s my right to protest.

Usually, Microsoft Word spell check lets me know when am wrong. A simple trick is to say it out loud using “it is”. You don’t need one if it doesn’t make sense with the apostrophe.

Lose and loose

Lose is the opposite of win. Loose means not tightly fixed or to set free.  It becomes a grammar error when you use “lose” in a sentence instead of “loose”.


  • If you loose to Tobi on Sunday, you won’t receive the reward.
  • The hinges on the door are lose.


  • The skirt was loose
  • What happens if I lose to Kike?

That vs Who

When I was preparing to take a UK English test, one of the lesson notes focused on the correct use of “that” and “who”. Use “who” when you’re writing about people and “that” for inanimate objects.


  • Stephen is a smart guy that never fails a test
  • The Eiffel Tower is a place who inspires romance


  • Stephen is a smart guy who never fails a test
  • The Eiffel Tower is a place that inspires romance

Less vs Fewer

Use “less” when referring to things or people that cannot be counted or doesn’t have a plural form. Use “fewer” when referring to people or things in the plural.


  • We’re offering a 25% discount on 10 items or less
  • There are less than 30 people on the ship
  • My work shoes cost fewer than $10


  • We’re offering a 25% discount on 10 items or fewer
  • There are fewer than 30 people on the ship
  • Philip spends less time in the classroom than in the science laboratory

Starting a sentence with “me” and ending a sentence with “I”

It is wrong to start a sentence with “Me”. For instance, saying

  • Incorrect – “Me and Titi went on a run this morning.”
  • Correct – “Titi and I went on a run this morning”.

It also applies to end a sentence with “I”.

  • Incorrect – The girls came to hang out with Rachel and I”.
  • Correct – “The girls came to hang out with me and Rachael.”

Overusing apostrophes

Usually, an apostrophe indicates possessions or missing letters. For instance, using “it’s” in place of “it is” or “they’re” in place of “they are”. Sometimes, people use an apostrophe in their name. Such as, “The Coker’s” instead of “The Cokers.” This is the correct way to describe a family without mentioning individual names.


  • Rap music was powerful in the 1990’s.
  • The Smith’s will be joining us for our annual reunion.
  • Long trousers were trendy in the 70’s


The 60s was the time of Rock and Roll

The Johnsons will join us for dinner

The dangling participle

The dangling participle damages the flow of your writing and makes it difficult for the reader to understand the sentence.


  • After rotting in the store for days, Sheila brought up some oranges

Eeeessshhhhh……who wants a rotten orange? Anybody?

  • While driving to school, the sun looked beautiful.


  • After rotting in the store for days, Sheila brought up some of the bad oranges
  • While driving to school, I noticed the sun looked beautiful

The participial phrase that begins the sentence is the wrong modifier for what follows next. The opening phrase should modify what follows or you have a dangling participle that confuses your readers. Restructuring the sentence makes it clear which word(s) the modifier describes.

Incorrect use of semicolons and colons

When writing, use semicolons to join ideas or parts of a sentence that has an equal rank or position. Ideally, these parts should be able to stand on their own. Colons are used to introduce a list, a noun phrase or noun. Colons are also used to separate independent clauses when the second explains the first.


I went to see Jeremy today; he gave me some grapes, apples and a banana.

Oz was my favourite TV shows in the 90s; in fact, it is my favourite TV show of all time.


There are three types of wood: oak, cherry and walnut.

I have assigned three officers to your team: Kelly, Jason and Mitchell.

Complement vs Compliment

Complement supplements or adds to something else. A compliment is saying something nice about a person.

Complement – We can complement the leftover soup with a loaf of bread

Compliment – Theresa, you look stunning this morning.

Specially and Especially

These two words sound the same so it’s easy to see why you might make a grammar mistake.

Especially means particularly, primarily or mostly. It is an adverb that singles out one thing or a person over all others.

  • I was especially impressed with the way you cooked the lamb.
  • Kunle despised outdoor activities, especially running.

Specially means something designed for a specific person or purpose

  • Jane was specially invited to dine with the Queen
  • The Oscar awards are a special occasion


As a rule of thumb, avoid grammar mistakes in your content. It helps you stand above the fold and raise the credibility of your company. Your best move? Hire an editor or an experienced copywriter who is well-versed in creating and editing content for your target audience.

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