Be Sure to Dot Your is!

By Maeve Maddox

A reader asks:

What is the correct way to write,
“there are three two’s in the English language”.

The short answer is:
There are three twos in the English language.

A more thorough answer requires a look at

1. the rule for forming the plural of letters, acronyms, symbols, and words regarded as words, and

2. the intended meaning of this particular sentence.

1. How to form the plural of letters, numerals, symbols, and words used as words

The Walsh Plain English handbook (widely used in American schools from 1939 into the 1970s) gave this rule:

Form the plurals of letters, symbols, figures, and words regarded as words by adding ‘s, or sometimes just s: Ex. Dot your i’s, cross your t’s, and make your 3’s (or 3s) plainer. You have too many and’s (or ands) in this sentence.

In 2009, the Purdue Online Writing Lab (OWL), an excellent and authoritative guide to written English, gives this rule:

The plurals of single capital letters, acronyms, and Arabic numerals (1,2,3,…) take an -s WITHOUT an apostrophe:
• Z (the capital letter Z)–Zs
• UPC (Universal Product Code)–UPCs
• ATM (Automatic Teller Machine)–ATMs
• GUI (Graphical User Interface)–GUIs
• 3 (the Arabic numeral 3)–3s

The OWL handout Forming plurals of lowercase letters carries this notation:

Apostrophes are used to form plurals of letters that appear in lowercase; here the rule appears to be more typographical than grammatical, e.g. “three ps” versus “three p’s.” To form the plural of a lowercase letter, place ‘s after the letter. There is no need for apostrophes indicating a plural on capitalized letters, numbers, and symbols (though keep in mind that some editors, teachers, and professors still prefer them).

My take on the use of the apostrophe to form any kind of plural is

avoid doing it if you can make your meaning clear in any other way.

Using ‘s to form the plural of symbols feeds the uncertainities of young writers who imagine that the apostrophe is the sign of the plural and write such things as The dog’s ran in the park. Or The dogs’ ran in the park. I’ve had students so mesmerized by the apostrophe that they wrote his as hi’s and goes as goe’s. Because of such experiences I balk at forming any kind of plural with ‘s.

In most cases no confusion results from adding a plain s to a numeral:
His 3s look like 8s. Or to an acronym: All the ATMs had been vandalized.

Adding s to a letter is tricky, as in the title of this post. The intended plural is looks like the verb is. Capitalizing the letter can help, but not in every case. Ex. Take more care in forming your As, Ts, and Is.

My solution is to resort to quotation marks: Take more care in forming your “a”s, “t”s, and “i”s.

I’m not entirely happy with my solution, but I prefer it to using the apostrophe to form a plural.

2. The sentence There are three twos in the English language.
Spoken, the sentence is a great way for a teacher to introduce the three English words that are pronounced [tu:]: to, two, and too. Attempting to put the sentence into written form, however, presents problems. For one thing, it spoils the pun. For another, there’s only one two in English.

Link to Owl Writing Lab

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14 Responses to “Be Sure to Dot Your is!”

  • Brandon


    I’m wondering if this would be a more . . . preferable solution to your quotation solution:

    Dot your -Is and cross your -Ps. Maybe even combining the similar technique of italicizing the title of a novel and leaving the pluralizing -S in Roman type.


    Dot your -Is and cross your -Ts.

    The hyphen connecting a letter would be the indicator that what is connected to it is a letter-as-a-noun, and the italics would help make it more . . . obvious that the -s is the plural morpheme.

    What say you?

  • Maeve

    Please tell me where to look in the OED for forming
    the plural of the letter i as ies.

    All I could find in the big OED is:
    Illustrations of the literary use of the letter:    a. simply. (The plural appears as Is, I’s, is, i’s.)

    Ask Oxford has this:
    in the plurals of single letters: 
There are only three s’s in `Christmases’. 
Mind your p’s and q’s. 
(Even here, the capital letter would not need the apostrophe.)


  • jb

    according to the oxford english dictionary, the plural of i would be ies.

  • Al G.

    I have referred to Roy Copperud’s Dictionary of Usage and Style (copyright 1964) for years, at the suggestion of a journalist. Copperud said that “conservative usage” still calls for apostophes to indicate the plural of a letter, sign, symbol or other non-word but there was (in 1964) a strong trend away from it. An inflexible rule calling for the omission of apostrophes can lead to trouble now and then, as an As, which comes out more intelligently as A’s. He argued against inflexible rules.

  • Grace S.

    Bryce (#7), those would be “Elvises,” since “Elvis’s” would be a possessive and whatever Elvis owned would have to follow. Punctuation, grammar, and spelling rules, when followed and understood, absolutely contribute to more precise communication!

  • Maeve

    You raise a good point. I’ll respond with a post next week.

  • Tim ‘Gonzo’ Gordon

    I had a discussion with someone just the other day regarding acronyms and came to the conclusion that an acronym is a word formed from the initial letters of a name. I would disagree with your observation that ATM is an acronym since people don’t speak it as a word; they merely say A – T- M.

  • Bryce

    To make matters even more confusing…consider proper nouns that end with the letter “s”.

    If there’s more than one Elvis impersonator, are they “Elvis’s” or “Elvises”?

  • GoingLikeSixty

    So I’ve been wrong in referring to my staff as C3PO’s. C3POs. Gotcha.

    “Be more careful forming the letter a, t, and i.”

  • Alan

    I prefer to use capitals, or failing that, where possible italics (on the letter, but not the pluralising ‘s’). Apostrophies, where they are not needed, just look ugly and often uninformed to me.

  • Mulled Vine

    I don’t know how you do a grateful smiley, but assume there is one here :-D. I’ve always wondered about this.

  • Joy-Mari

    I use an apostrophe when the reverse means forming a new word, eg, is instead of i’s. I prefer using as few apostrophes as possible, and even fewer quotation marks.

  • Torsten Herrmann

    Thanks a lot. In German a lot of people also use apostrophes and they are (almost) always wrong. We call this phenomenon Apostrophismus or Apostrophilie. I guess people try to be cooler by using English forms or it is based on the fact that we learn English grammar later than German. Maybe it is a form of hypercorrection which means people try to use high-class language but fail.

    First time the mistake appeared in genitive forms (Peter’s instead of Peters, which is correct in German), than in plural (CD’s instead of CDs) and later some people started to separate the last letter wherever they thought (Nudel’n instead of Nudeln; remark that we form plural not only with “s” but it doesn’t depend on the fact if it is plural or not). Maybe you like this overview on German mistakes:

  • Stephen

    Or as humor author Dave Barry once observed years ago, the purpose of the apostrophe is to indicate a following “s”.

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