As someone who regularly switches between keyboard layouts, I have a problem: I have at least three keys that can be used as an apostrophe, but I don't know which one is the correct one. Compare:

• Backtick: Hamlet`s father
• ASCII Apostrophe: Hamlet's father
• Acute accent: Hamlet́s father
• Single closing quote: Hamlet’s father

Do you know which one is the right one? If not, this small guide is for you. But you'll have to endure a lot of theory first.

The problem here is that using your keyboard requires mixing three different concepts: which key you pressed, which character it represents, and how is it visually represented. To explain that in clearer terms, let's take the backtick as an example.

The key itself can move around. The backtick key is located below the tilde (~) in a US keyboard, to the left of the backspace key in a German keyboard, and under the caret (^) in a Spanish keyboard.

Internally, this key is called "Grave accent" in ASCII but programmers know it it as "backquote" or "backtick". When you press it you send a code to your computer that, if you were using ASCII, would be reflected as the 0x60 hexadecimal value. And here we make another distinction: if your computer is configured to do so, this code can be interpreted as a dead key that only exists to modify the next character. If you want to type the è in the French word très (very) you use the combination <Grave accent key> + <e key>. If your computer is not configured in this way then you simply get a backtick.

But here we have a very subtle difference between a backtick and a Grave accent. The Grave accent is a modifier, changing the sound of the letter underneath. Therefore, it cannot exist by itself. If you see the character ` alone then it is not a Grave accent, it's a backtick. They both look the same, but they have different meanings.

Your program is another factor: some programs may replace the character you are using because it's very likely that you are using it wrong. If I type the double quote character (") in Microsoft Word it may be replaced by an Opening double quote (“), a German opening double quote („), an English closing double quote (”), or a German closing double quote (“, which is the same character as the Opening double quote in English).

And then we have the issue of fonts. Some fonts may represent two different characters in the same way, or straight up ignore it. If you have been staring at some of the quotes I mentioned above and see no difference, well, maybe that's why.

So back to our original question: what is each key good for?

• The backtick quote (`) has no meaning in typography at all. The only reason a non-programmer would use it would be to type a Grave accent.
• The apostrophe (') is the one I need for daily use. In truth, Unicode defines a different character as a "true" apostrophe (we'll get to that soon), but not all keyboards can generate it. Therefore, and just like the double quote example above, it is okay to use it.
• The Acute accent (́) should only be used as a modifier. You can see that it insists on modifying whichever character is next to it, because it has no meaning by itself.
• The Single closing quote (’) can be generated under certain combinations of keyboard and local configuration. If your keyboard supports it, this is the preferred key to use for apostrophes.

There are plenty other versions of the quote character that can be used. This list of commonly confused characters has been of great help, while this technical description of the apostrophe character also provides more info than you thought you needed. Sure, it may sound like a lot of work. But you'll thank me next time you need to write a phrase like “In a Déjà vu, René corrected ‘It’s x′, not x″’” knowing full well that you are right.