Although we have written before about common grammar mistakes in various settings, with the entering of the third trimester of 2026, we have considered that it is time to look at some of the common grammar mistakes people make in the modern workplace.
You are aware that fixing your grammar mistakes can help you improve your English writing skills. In a competitive business world, this can also help you communicate more clearly, build a more professional image, and find new business opportunities.
Good grammar is not about trying to sound overly formal or complicated. In the workplace, it is mainly about making sure that your message is clear and easy to understand. A small grammar mistake in an email may not cause a serious problem, but repeated mistakes can affect how other people perceive your communication skills. This can be particularly important when you are communicating with clients, business partners, managers, or potential customers.
In what follows, we will review some of the most common grammar mistakes that people often commit, even in professional settings. We hope that after reading this article, you will become more aware of the errors you may often make and, with it, improve your English writing skills.
In the past, we tackled the topic. If you want to read more about the topic, you can start with the following article on the most common grammar mistakes. We also recommend this piece, which we think will be helpful if you want to learn more about the most common grammar errors.
1. Subject–verb agreement
We have discussed this issue previously, and it is probably one of the most important grammatical errors to include in this list.
Subject–verb agreement means that the verb in a sentence must agree with its subject. In other words, a singular subject normally requires a singular verb, while a plural subject requires a plural verb.
Wrong:
The list of requirements are attached.
Correct:
The list of requirements is attached.
The extra noun “requirements” tricks people into matching the verb with the wrong noun. However, the real subject of the sentence is “list,” which is singular. Therefore, the correct verb is “is.”
This type of mistake is particularly easy to make when a sentence contains several nouns. Consider the following example:
Wrong:
The results of the latest survey shows a significant improvement.
Correct:
The results of the latest survey show a significant improvement.
The phrase “of the latest survey” provides additional information, but it is not the subject. The subject is “results,” which is plural.
Subject–verb disagreement is repeatedly identified as one of the most common errors in professional writing. Be very careful about what the real subject of the sentence is, especially when other nouns appear between the subject and the verb.
This may seem like a basic rule, but basic mistakes are often the ones that survive proofreading because we read what we expect to see rather than what is actually written.
2. Your vs. you’re
This is extremely common in workplace emails and instant messages. Mixing between the two can make you appear less careful and, in some situations, highly unprofessional.
Wrong:
Your going to receive the report tomorrow.
Correct:
You’re going to receive the report tomorrow.
The difference is simple:
Your = possession
You’re = you are
For example:
Please send me your report.
You’re going to receive the report tomorrow.
One useful way to check yourself is to replace “you’re” with “you are.” If the sentence still makes sense, “you’re” is probably the correct choice.
For example:
“You’re going to receive the report tomorrow” becomes “You are going to receive the report tomorrow.”
That works.
On the other hand, “Please send me you’re report” does not work when expanded to “Please send me you are report.” Therefore, the correct word is “your.”
This is particularly useful for our audience because it is a very basic error that can make otherwise competent professional writing look careless. In a quick message between colleagues, the mistake may be overlooked. In a proposal, business email, or message to a potential client, however, it can create a different impression.
3. Its vs. it’s
Another classic is not differentiating between the possessive “its” and the short form for “it is,” “it’s.”
Wrong:
The company changed it’s pricing structure.
Correct:
The company changed its pricing structure.
Its = possessive
It’s = it is / it has
The interesting point here is that apostrophes do not automatically indicate possession. That can be counterintuitive because, with ordinary nouns, an apostrophe often does indicate possession.
For example:
The company’s policy
The manager’s office
The client’s request
However, “its” is different. When you are showing possession, you use “its” without an apostrophe.
For example:
The company changed its policy.
The business increased its prices.
The software has lost its connection.
When “it’s” is used, it is a contraction. It can mean “it is” or “it has.”
For example:
It’s important to check the figures.
It’s been a difficult quarter.
A simple test is to replace “it’s” with “it is” or “it has.” If the sentence still makes sense, the contraction may be correct. If it does not, you probably need “its.”
This is another small mistake that can distract readers from the actual message. In professional writing, avoiding these errors helps your writing appear more polished without making it unnecessarily formal.
4. Apostrophes used to make plurals
This one is particularly common in business documents, and it can create confusion for the reader.
Wrong:
Please review the following KPI’s.
Correct:
Please review the following KPIs.
An apostrophe generally indicates possession or a contraction—not a plural.
This becomes especially relevant with abbreviations:
CEO’s ❌
CEOs ✅
KPI’s ❌
KPIs ✅
PDF’s ❌
PDFs ✅
The same principle applies to many other abbreviations and acronyms used in the workplace. If you are simply referring to more than one item, you normally do not need an apostrophe.
For example:
The company has several CEOs.
We reviewed the latest KPIs.
Please send the PDFs to the client.
There are some exceptions and style differences in English, but using an apostrophe simply because a word or abbreviation ends in a particular letter is generally not necessary.
Harvard’s writing guidance specifically distinguishes possessive apostrophes from ordinary plurals. This is worth remembering because business writing often contains abbreviations, numbers, and short forms, which makes this mistake especially easy to make.
The important question is simple: are you showing possession, or are you simply making the word plural? If it is plural, an apostrophe is usually not needed.
5. Comma splices
A very common problem in hurried business writing is the comma splice. Although this can be seen as a more advanced error, committing it can make your writing appear unprofessional.
Wrong:
We have completed the project, we can now move to the next phase.
Correct:
We have completed the project, and we can now move to the next phase.
Or:
We have completed the project. We can now move to the next phase.
A comma alone generally cannot join two independent clauses.
An independent clause is a group of words that can stand on its own as a complete sentence. In the example above, “We have completed the project” is a complete sentence, and “we can now move to the next phase” is also a complete sentence. Simply placing a comma between them creates a comma splice.
There are several ways to correct the problem. You can use a full stop and create two sentences, or you can use a suitable coordinating conjunction such as “and,” “but,” or “so.”
For example:
The client approved the proposal, and we can begin the work.
The deadline is approaching, so we need to finish the report.
The figures look promising, but we still need more information.
The figures look promising, but we still need more information.
In some cases, a semicolon can also be used:
The client approved the proposal; we can now begin the work.
The important thing is not to let a comma do the job of a stronger piece of punctuation.
Business writing often suffers from comma splices because people write quickly and try to connect several thoughts in one sentence. If you notice that a sentence contains two complete thoughts joined only by a comma, stop and check whether you need a conjunction, a semicolon, or a full stop.
6. Commas in the wrong places
This is broader than comma splices.
People often insert commas where they would naturally pause when speaking. This is not how punctuation works, so you cannot put a comma wherever you want to place one.
Wrong:
Our sales team, has exceeded its target.
Correct:
Our sales team has exceeded its target.
There is no reason for the comma in the first sentence. “Our sales team” is the subject, and “has exceeded its target” is the rest of the sentence. The two parts should not be separated by a comma.
Another common problem is adding unnecessary commas around short phrases or between a subject and its verb.
Wrong:
The new marketing strategy, has produced excellent results.
Correct:
The new marketing strategy has produced excellent results.
The same principle applies when people add commas simply because they would pause while speaking. Written punctuation does not always follow the pauses we make in conversation.
At the same time, commas can be important when they improve clarity.
For example:
After reviewing the proposal, we decided to move forward.
Here, the introductory phrase is separated from the main clause with a comma, making the sentence easier to read.
The workplace is particularly vulnerable to comma mistakes because employees often write quickly rather than deliberately. Emails, instant messages, reports, presentations, and other business documents are frequently produced under time pressure. As a result, punctuation is often treated as an afterthought.
Indeed’s current 2026 guide also lists unnecessary commas among common errors.
The main lesson is that punctuation should serve a purpose. A comma should not simply be added because you would pause at that point when speaking. Look at the structure of the sentence and consider whether the comma separates information that actually needs to be separated.
Why these mistakes matter in the workplace
None of these errors is likely to prevent someone from understanding your message. That does not mean they are unimportant.
Professional writing is often judged quickly. A client may read an email in a few seconds. A manager may scan a report before a meeting. A potential business partner may form an impression of your company from a single message.
This is why paying attention to grammar can be worthwhile. You do not need to write in an unnecessarily complicated way or use difficult vocabulary to sound professional. In fact, clear and simple English is often more effective.
The goal is to make your writing easy to understand and difficult to misunderstand.
If you regularly make some of these common grammar mistakes, do not worry. The first step is simply to become aware of them. Once you know what to look for, proofreading becomes much easier.
Before sending an important email or document, take a moment to check the subject and verb, contractions such as “you’re” and “it’s,” apostrophes, and commas. These small checks can make a noticeable difference.
And, of course, continue working to improve your English writing skills. The more you read, write, and review your own mistakes, the easier it becomes to recognize them before someone else does.
