How do I write a single letter in a sentence?

Question

Example: Did you notice how the letter R is pronounced in American English?

Do I write like the example above, or do I need to italicize it?

Answer 1

It depends entirely on what style guide you follow.

For instance, the following are guidelines from two of the most well-known style guides. Note that their guidance is (mostly) contradictory.

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The Chicago Manual of Style (17th ed.), 7.64, says to use italics:

Individual letters and combinations of letters of the Latin alphabet are usually italicized.

      the letter q
      a lowercase n
      a capital W
      The plural is usually formed in English by adding s or es.
      He signed the document with an X.
      I need a word with two e’s and three s’s.

This follows from Chicago 7.63, which discusses actual phrases:

When a word or term is not used functionally but is referred to as the word or term itself, it is either italicized or enclosed in quotation marks. Proper nouns used as words, as in the third example, are usually set in roman.

      The term critical mass is more often used metaphorically than literally.
      What is meant by neurobotics?
      You rarely see the term iPhone with a capital i.

Although italics are the traditional choice, quotation marks may be more appropriate in certain contexts. In the first example below, italics set off the Spanish term, and quotation marks are used for the English. In the second example, quotation marks help to convey the idea of speech.

      The Spanish verbs ser and estar are both rendered by “to be.”
      Many people say “I” even when “me” would be more correct.

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The Associated Press Stylebook says to use quotation marks:

Question:

When referencing a letter of the alphabet, how should the letter appear? For example: "Gnosticism, with a silent g." How should the letter g appear: in single or double quotation marks, italicized or in some other form?
from Plano, TX on Aug. 22, 2018

Answer:

If the reference is within a quote, then put single quote marks around the "g." Otherwise, use double quote marks. AP doesn't use italics.

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So, if you follow Chicago, you would normally use italics; if you follow AP, you would normally use quotation marks. But other style guides may suggest something entirely different.

As for whether or not single letters should be in uppercase or lowercase, Chicago doesn't give specific guidance one way or the other (although if I look at their examples, they tend to lean toward lowercase unless there is a specific need for uppercase), and AP says to use lowercase.

The main point is that this isn't a matter of grammar, but of style. And there is no single style. So, either follow a particular style guide or simply choose your own style and be consistent about it.

Answer 2

In MLA Format (the standard American format for writing papers), the only letters that require a distinction to be made are "I" and "A," since they are words as well as letters.

In other words, you do not need to italicize, put in quotes, or bold the letter R. (Just capitalize it.)

Answer 3

I would Recommend using "Quotes" or Emphasis (Italics) when trying to write a Single letter in a sentence as an example.

Depending on where this sentence will be placed, you can be less formal about it and simply use an Uppercase letter, or an Uppercase letter that is Bold or has a heavier font weight.

Did you notice how the letter R is pronounced in American English?

Did you notice how the letter "R" is pronounced in American English?