20 Rookie Grammar Errors Even Professional Writers Make

Everybody makes mistakes. Some mistakes are simple, harmless to everything but our pride, and easy to fix. Others are huge, expensive, and humiliating.

For example, an author I know had a book with a major publishing company. Two days before publication he received his author copies, only to discover the entire print run had put about a third of the pages out of order. That’s a huge mistake.

Smaller mistakes we can make as writers are those little grammar issues we don’t notice, some editors don’t notice, and very few readers notice — except that one who mentions it in your review and all over social media. 

Today I want to discuss 20 of those errors. These are common mistakes you’ll sometimes still see in published, fully edited, professional books. It’s my hope you’ll internalize these and avoid them…so you can go on to make new, unique, and exciting grammar mistakes of your own! 

20 All Too Common Grammar Errors

1. Bi and Semi

The prefix “bi” means “two” or “twice”. The prefix “semi” means “in half”. So “biweekly” means “every other week” and “semiweekly” means twice a week. 

2. Literally Killing Your Prose

I know all the kids these days are using “literally” to mean “I want to emphasize this next statement”, kind of like a verbal version of putting words into bold type. That’s fine, and you might get away with this in dialogue, or with a narrator of a certain age. 

Otherwise, use the word sparingly, and only when you want to emphasize that a thing is actually happening, and literally for real.

3. Using “Myriad” as a Noun

A lot of people use myriad in a sentence like this: “He had a myriad of ways to accomplish his goals.” None of those people are right. 

Myriad is an adjective. “He had myriad ways to accomplish his goals” is correct.

4. Incomplete Comparisons

Consider the following sentence: “My boyfriend is taller, stronger, and a better kisser.”

It feels right on the surface, but it never tells you what he’s taller, stronger, and a better kisser than. Sure, it might be implied that he’s being compared to the speaker’s previous boyfriend, but it’s not specified. Good writing is specific.

5. Me vs. I Issues

There’s some history to this. For a while, I guess, a lot of people used “me” instead of “I” in ways that got them humiliated in public, so now we have this backlash where people use “I” too much when “me” is the proper word. It’s usually easy when you’re just speaking about yourself. It’s when the sentence includes another person or thing that we get into trouble.

The actual rules are complex, but there’s a simple rule of thumb. Say the sentence without the other person or thing. If it makes sense that way, then you used the right word. For example, take these four sentences:

  • They went to the store with my father and me. 
  • They went to the store with my father and I.
  • Me and my father went to the store.
  • My father and I went to the store.

Take out the father. “They went to the store with me” is correct because “They went to the store with I” sounds wrong and is wrong. “I went to the store” works, but “Me went to the store” does not, so “My father and I went to the store” is right. 

6. Of vs. Have

I should have put this one higher on this list. I should have put this one lower on the list. Written down, that’s how statements like that should be written.

However, in spoken language, the “have” often gets pronounced as the contraction: “should’ve”. That sounds enough like “should of” that some folks end up thinking that’s the phrase, and writing it like that.

Just remember: “shoulda, coulda, woulda” means “should have, could have, would have.”

7. Unintentional Redundancy

Redundancy is the enemy of both good grammar and compelling writing. Unfortunately, some unintentional redundancy has crept into our everyday language. Consider these three examples:

  • Unthaw
  • First year anniversary
  • ATM Machine
  • Hot Water Heater

Unthaw and thaw refer to the same thing, even though “unthaw” would technical mean to freeze again. An anniversary refers to years by default. ATM stands for Automated Teller Machine, so you’re actually saying “Automated Teller Machine Machine”. Water enters the heater cold, so it’s not heating hot water. 

Once you start looking for these, you’ll find myriad other examples (see what I did there?). Eliminate them when you do.

8. Misheard Aphorisms

This one often happens because how we speak English is different from how we write English. Often our minds insert words that feel like they make sense, but the result isn’t the original aphorism. 

Take for example “first come, first served.” We know what it means, but a lot of people write it “first come, first serve” without the d at the end. See also “I could care less” when people mean and should write, “I couldn’t care less.”

Some more examples:

  • Nip it in the butt (instead of in the bud)
  • A mute point (instead of a moot point)
  • Deep-seeded (instead of deep-seated)
  • Extract revenge (instead of exact revenge)

9. Misspelled Aphorisms

In addition to misheard aphorisms, you also get aphorisms people pronounce and hear correctly, but misspell. For example, it’s “waiting with bated breath”. Many spell it “waiting with baited breath”, maybe imagining hiding in wait for some kind of prey to come out of a hiding hole. 

But it’s ‘bated, short for “abated”, as in “with breath stopped or much diminished in anticipation.” Some other common examples include:

  • Peaked my interest (instead of piqued my interest)
  • Do diligence (instead of due diligence)
  • Tow the line (instead of toe the line)

10. Emigrated vs. Immigrated

This one is simple to remember, but I don’t think it gets taught very often. Plus the words sound very similar and mean closely related things. For the record:

Emigrate means to leave a place, usually a country, with the purpose of beginning a new life someplace else. 

Immigrate means to arrive at a place, usually a country, with the purpose of beginning a new life there. 

Everybody who emigrates also immigrates. Everybody who immigrates also emigrates. You emigrate from one place when you immigrate to another. 

11. Abuse of the Common Semicolon

If you have two independent clauses that could be complete sentences on their own, you can use a semicolon to make sure the reader associates them closely. “I love her. She is my everything” could be “I love her; she is my everything.”

A semicolon does the work of conjunctions like and, but, and or. Most of the time, your writing will be better if you either use the conjunction with a comma, or write two short sentences. 

You can also use a semicolon as a sort of “super-comma” when dealing with long sentences including phrases which themselves use commas. For example: “I had two choices: the science club, which used blowtorches, laughing gas, and explosives; or the football team, who had girls, parties, and popularity.”

Like with the other use of semicolons, usually your writing is better if you just make more sentences. Use semicolons with caution. 

12. What Penultimate Actually Means

This one’s pretty specific and very nerdy, but being a good writer means being specific and nerdy with our word choice. Every so often, you’ll find people who use the word “penultimate” to mean “even better than ultimate” or something like that. It’s nonsensical, since “ultimate” means “last”, and you can’t have something more last than last. It’s like saying “very unique”.

Penultimate means “second to last”. “To” is the penultimate word of the sentence you just read. 

13. The Apostrophe Problem

I hope I’m preaching to the choir here, but there is a widespread issue when it comes to apostrophes and possessives. It breaks down like this:

  • Show possession by putting an apostrophe-s after the possessing word: John’s ball means the ball belongs to John. The company’s van means the van belongs to the company. 


  • The possessing word is “it.” With it, there is no apostrophe. If the chainsaw belongs to it, then you say its chainsaw. Not it’s chainsaw. “It’s” only ever means “it is.”

I have no idea why. Also, never, ever, ever, ever use an apostrophe when you’re making something a plural. A whole bunch of cannibals is never spelled “cannibal’s”

14. That Which Must Not Be Named

Here’s the thing about the word “that.” Most of the time you can get rid of it entirely. Consider the following sentences:

  • The car that my dad built.
  • I knew that some people were afraid of flowers.
  • Please tell her that I called.
  • For crying out loud, you know that I love you.

Now, consider these sentences:

  • The car my dad built.
  • I knew some people were afraid of flowers.
  • Please tell her I called.
  • For crying out loud, you know I love you.

None of those sentences were hurt by removing the word “that”. Most, maybe all, were improved. Not every usage of the word makes writing worse, but it’s worth considering every instance in your writing. Pull it out, read the sentence, and if it still works leave it out. 

15. Em vs. En Dashes

There are two kinds of dashes in written english: the shorter en-dash (-) and the longer em-dash (—). You cannot use them interchangeably. 

Use an en-dash to express ranges and spans, or to hyphenate words. A recipe takes 20-30 minutes to finish. The course should take 3-4 weeks. It was a high-pressure situation.

Use an em-dash to separate things, for example between a quotation and the attribution (“I got a bad feeling about this” — Han Solo), or when putting a side comment into a sentence (I really hated him — everybody hated him, if you get down to it — but he was a permanent part of the office). 

16. Capitalization in Titles

Okay. This is complicated, in part because the rules are different for different mediums.

We’ll start with the traditional rules for capitalizing a title. There are four rules:

  1. Capitalize the first word and the last word, even if one of the rules below says otherwise.
  2. Capitalize nouns, verbs, adjectives, adverbs, and pronouns
  3. Do not capitalize articles, conjunctions, or prepositions
  4. Do not capitalize the word to

Using those rules, the following titles are properly capitalized:

  1. Beat It!
  2. My Favorite Dog
  3. My Favorite Dog and Least Favorite Cat
  4. My Dog Went to the Movies

If you follow those rules, you won’t go far wrong. However, some internet titling uses  something called “sentence case”, where you capitalize a title the same way you capitalize a regular sentence. This is because online publishing allows header formatting to emphasize titles instead of capitalization. Don’t worry about this too much. If you work for a site that uses it, they’ll tell you.

17. Other Capitalization Woes

There’s a lot of other little-known capitalization rules and mistakes. We all know to capitalize the first letter in a sentence, and proper nouns like names of people and countries, but here are a few other rules to keep in mind. 

  • Capitalize titles when preceding a name, but not after a name: “Governor Nishimura”, not but not “Nishimura, governor of our state.”
  • Capitalize a family relationship when it’s used like a title, but not simply as a description: “Uncle Bob is my father’s brother.”
  • Capitalize references to a deity when it's used like a name, but not simply as a noun: “I prayed to God because he is the god I chose for myself.”
  • Names of historical periods and eras count as proper names for purposes of capitalization: “The Age of Enlightenment had a strong influence on colonial American thought.”
  • Do not capitalize the letters when spelling out what an acronym stands for, but do capitalize the letters in the acronym: “SCUBA stands for self-contained, underwater breathing apparatus.
  • Do not put a capital letter after a colon, period, or other punctuation that doesn’t end a sentence: “I liked her. She was nice” but not “I liked her, She was nice.” 
  • Capitalize directions only when they are part of a name: “Southwest Airlines”, but not “Walk Southwest for three miles”

Many others exist, but the seven above are the ones I have the most trouble remembering, and that I see others mistaking most often.

18. i.e. vs. e.g

A lot of people use these interchangeably, thinking they both mean something along the lines of “for example”, but that’s not proper usage. Instead:

  • i.e. is short for the Latin phrase “id est” and means “in other words”, and is used to clarify your point. (The literal translation is “That is.”)
  • e.g. stands for “example given”, and adds color though giving an example

“I love to run marathons, i.e. suffering greatly to travel by foot a distance better suited to a car” is correct. “I love distance running, e.g. 10ks, half-marathons, and marathons” is also correct. 

One trick is to think of “i.e.” as standing for “in essence”, and “e.g.” meaning “for egzample”. 

19. Leaving Us Hanging

Or dangling, as some grammarians would have it. People make this mistake when they write a descriptive phrase but attribute it incorrectly. For example:

  • Perusing the menu, it had lots of meat but not much for vegetarians.

The sentence sort of implies that somebody perused the menu and made the observation about its carnivore vs. herbivore offerings. But instead it says the menu was perusing itself. Sentences like this usually benefit from added information so you clarify who is doing whatever action happens in the descriptive phrase. 

20. The Comma Chameleon

My high school English teacher used to accuse students of using commas like a chef sprinkling pepper from a shaker onto the page. A lot of even accomplished writers (and editors!) seem to insert and remove them at random. 

Really, though, there are three times to use a comma:

  1. Separating elements in a series: The book, the bell, and the candle were in her backpack.
  2. To separate independent clauses in a sentence: My sister can be rude, but she makes me laugh.
  3. To separate an introductory word or phrase from the sentence that follows: Last year, I didn’t know how to swim. 

That’s it. I think the issue here is that commas are pauses in the flow of the written word. People sometimes want to put them in where they would pause during natural speech, or to eliminate them where they belong but people wouldn’t necessarily pause while speaking. Just remember the rules above, and that written and spoken language are different. 

Bonus Error: The Oxford Comma

More specifically about commas, the comma that appears between the last two items in a series is called an Oxford comma. It’s optional, and a surprisingly large number of people on the internet have incredibly strong opinions about it. If you are following a specific style-guide, then you should use one when it's called for or remove them when it isn't.

If you don't have a specific style guide, then I would generally recommend that you include the Oxford Comma because it increases the clarity of what you are trying to say.

For example, here are 3 sentences that mean something different when you don't include the Oxford Comma:

  • “My heroes are my parents, Batman and Wonder Woman.” (Rather than 3 heroes, you are implying that your parents are specifically Batman and Wonder Woman.)
  • “I'll bring the coffee, donuts and my laptop.” (Rather than bringing 3 items with you, you are implying that the coffee will be made out of donuts and your laptop.)
  • “The canning, processing, preserving, freezing, drying, marketing, storing, packing for shipment or distribution of: (1) Agricultural produce; (2) Meat and fish products; and (3) Perishable foods.” (This was from a real court case where Maine dairy delivery drivers won $5 million in a settlement against Oakhurst for not paying overtime because they argued that “packing for shipment or distribution” was written as a single action and not as two separate actions. Had the overtime exemption been written with an Oxford Comma then the law would have made it legal to avoid paying overtime.)

What Do You Think?

Is there one we missed? One you think isn’t actually a mistake, and you’re the only person who realizes how important it is to write that way? Do you have a great story about a time you, or another writer, messed one of these up to hilarious effect? Hop on our Facebook page and tell us about it. 

I’d love to see you there!