1. Compliment versus complement
A "compliment" is a kind word or gesture; flattery ("I considered it a compliment when someone said my dress was classic.").
"Complement" means to match or balance someone or something ("her organizational skills complement his creativity"; "the bedspread complements the color of the walls").
You can remember the difference by noting that the letter "e" appears twice in "complement"--the two "e"s complement each other.
2. Principle versus principal
The word "principle" means "value" or "moral" ("she has strong principles"). It is only used as a noun.
The word "principal" can be used as a noun or an adjective. As a noun, it refers to the head of an organization, like a school principal. As an adjective, it means "primary" or "main" ("The principal concern is that the merger won't go through.").
You can remember the difference by saying that you always want the principal to be your "pal" (how the end of the word is spelled). And your principal concern is often to make sure the principal stays your pal.
"None" is always singular.
Thus, "None of us are going" is incorrect. It should be, "None of us is going." Similarly, "None of these candidates have any class" is incorrect. It should be, "None of these candidates has any class."
The easy way to check yourself is to take out everything but "none" in a sentence and test the verb. The verb should always agree with the subject, which is none, and which is always singular.
To remember this, just think, "None, singular sensation...."
4. Capitalizing titles
Titles such as "president" and "prime minister" are only capitalized when they refer to a specific person. If I allude to President Obama, I capitalize the title; if I'm simply referring to the president, I do not.
- I was surprised when the President of the association interrupted us.
- It seemed strange that someone at the Director level would do such a thing.
- The best part of my day was when Director of Operations Jennings showed me how to play Candy Crush on my work machine.
- I couldn't believe the congresswoman had the audacity to say such a thing to me, but at least Senator Warren backed me up.
5. Capitalizing advanced degrees
Similarly, you only capitalize an advanced degree when referencing the specific subject. For example, you hold a Master of Arts in Communication, or a Master's in Communication. If you don't include the subject of the degree, you don't capitalize it - it's just, "I have a master's degree."
- I don't think we actually need someone with a bachelor's for this job.
- She already holds a BA in Electrical Engineering and a Master's in Computer Science, but wants to go back for a doctorate.
- He'd like to get a master's in the next year or two, depending on whether he wins the lottery.
6. Less versus fewer
If you're referring to things you can count (quantifiable), you always use "fewer." Thus, "We had dramatically less sales on Etsy this year" is incorrect. It should be, "We had dramatically fewer sales," because you can count the number of sales.
- There were less people at the rally this year than last. (Should be, "fewer people.")
- We received less survey responses than we'd hoped. (Should be, "fewer responses.")
- There was less support for the vice president than anticipated. (Correct.)
One way you can remember the difference is with "f"s: If you can feel it with your hands, it's fewer (or if it's finite, it's fewer).
7. Rein versus reign
"Reins" are things you use to control horses--hence the phrase, "Take the reins!"
"Reign" refers to a person being in power: "Queen Elizabeth reigned for nearly 50 years," or, "I am the reigning queen of Guitar Hero in my family."
Phrases often assumed to take "reign" but that actually take "rein":
- You need to rein it in.
- I want her to take the reins more.
- I'm giving you free rein on this project.
- Consumers continue to rein back spending.
For a long time, horses were the primary mode of transportation and a major part of everyday life. This history is reflected in the language; the correct word in a phrase about controlling something will almost always be "rein."
In a world dominated by hashtags and emojis, it's easy to forget how rich and varied a language English truly is. Here's celebrating all the intricacies and idiosyncrasies of one of the most beautiful languages on earth--may long it reign.