These two-letter words ending in -o are pronounced with the vowel /oʊ/: bo, go ho, jo, lo, no, so, and yo whereas do and to are pronounced with the vowel /uː/. Is there an explanation for the discrepancy in pronunciation?

  • I doubt anyone can provide any suitable answer to this. It's just one of the countless strange intricacies of the English language.
    – Urbycoz
    Commented Jul 18, 2012 at 10:36
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    Exec summary: no decision is made. Pronunciation came first, then spelling was made up, they tried to make things consistent, but this wasn't particularly successful in English (no authoritative academy), and pronunciation has changed over the (hundreds of) years.
    – Mitch
    Commented Jul 18, 2012 at 12:59
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    This has been closed as non-constructive, but I am reopening it to close it as a dupe instead. The simple answer is that the "o" in go was originally an /ɑː/, while the "o" in do and to was originally an /oː/. So they were always different to begin with, and even the Great Vowel Shift could do nothing about it, because different vowels shifted into different directions. Spoken language is primary; spelling is just a convention. So your question is kind of backwards.
    – RegDwigнt
    Commented Jul 18, 2012 at 14:26
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    Doesn't RegDwight's comment still answer the question though?
    – Andrew Leach
    Commented Jul 18, 2012 at 16:00
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    Yes, I'm hoping he expands on it and makes it a proper answer.
    – nohat
    Commented Jul 18, 2012 at 16:10

7 Answers 7


The question posed

Why is “go” spelled with the same vowel as “do” and “to” since it is pronounced differently?

makes an incorrect presupposition. That's the cause of the problem.
Deny the presupposition and the problem goes away.

That presupposition is that

English spelling represents English pronunciation.

This is False.

The fact is that the spelling of modern English words does not give more than a vague guide to their pronunciation.

Vowels, especially, are terribly inconsistent, because there are fourteen phonemic vowels in American English (see the list here -- there are even more in other dialects), all represented by only five vowel letters, in many traditional ways, all inconsistent. Each way was designed centuries ago by people who knew no phonetics, spoke many languages and dialects (not all of them English), and thought they were writing Latin.

Any dictionary will tell you the spelling of English words. A good dictionary (which American dictionaries are not, alas) will also give the pronunciation in IPA or Kenyon-Knott. Spelling and pronunciation are separate, and should be learned separately, like the singular and plural forms of German nouns.

So the answer is that go is spelled with the same vowel as do and to because that's how they're spelled. There is no other reason. No matter what your English teacher told you. Sorry; it's not their fault, though -- they were taught this lie, too.

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    The problem is that English spelling does represent English pronunciation, for most words, most of the time. It's more than just a vague guide. An educated person can guess the pronunciation of a word based on its spelling and be right the vast majority of the time. The exceptions to this all have explanation; spelling is not random.
    – nohat
    Commented Jul 18, 2012 at 17:09
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    Indeed, that's true. Provided one wishes to learn Middle English, historical phonology, English history and dialectology, and Indo-European linguistics. Then you can see the fossils and identify the species; but to everybody else it's just a bunch of rocks, and it's much simpler just to learn the pronunciations separately. Commented Jul 18, 2012 at 17:16
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    @JohnLawler I do want to learn all those things. We're supposed to be English language enthusiasts!
    – nohat
    Commented Jul 18, 2012 at 18:39
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    @nohat: I'm delighted to hear it. There are some materials here, here, and here. Commented Jul 18, 2012 at 19:09
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    English can be understood through thorough thought though.
    – Ramrod
    Commented Feb 16, 2016 at 4:37

How do we decide pronunciation for english words?

Pronunciation of many (probably all) English words has varied over time and from place to place.

As you have noted, spelling is not a foolproof guide to current pronunciation in any specific place. This is particularly true as spelling currently varies from place to place (e.g. color and colour).

We decide how to pronounce a written word in any of the following ways.

  • By hearing how people around us pronounce the word.
  • By looking in a dictionary that provides a guide to pronunciation.
  • By guessing based on how we most often pronounce other words with a similar spelling.

The result may be judged correct in some places at some times yet be judged incorrect elsewhere or elsewhen.

Why 'go' pronounce as 'go' and not 'goo' [as in 'do']?

The idea of standardised spelling is a relatively modern one. Shakespeare quite happily wrote his name using many different spellings. It was only with the advent of dictionaries that spelling gradually became frozen in whatever choice of letters the dictionary compilers selected. The early compilers do not appear to have been especially concerned about consistency between spelling and pronunciation. Noah Webster was a bit of an exception.

Words that today have similar spellings may have, in the past, had spellings that differed more widely and which reflected different pronunciations. Such words may have originated in different languages and have spellings adopted from those differing languages - which may have had different rules of pronunciation.

So the contradictions you identify might arise from an unfortunate convergence of spelling changes or from a difference in source language or even from an arbitrary change in pronunciation (e.g. in "the great vowel shift").


As Reg Dwight said in a comment, they have different historical pronunciations:

the "o" in go was originally an /ɑː/, while the "o" in do and to was originally an /oː/. So they were always different to begin with, and even the Great Vowel Shift could do nothing about it, because different vowels shifted into different directions.

Go and do happen to be spelled the same because in Middle English, the time period when much of the current English spelling system was formed, their vowels were fairly similar (/ɔː/ and /oː/ respectively), and there are not as many vowel letters in the alphabet as there are vowel sounds in English. But they have never been pronounced the same.


There are many, many more vowel sounds in English than the five traditional Latin vowels. So it is inevitable that the same letter will represent different sounds in different words.

At best, English spelling reflects Middle English pronunciation, not Modern English pronunciation. That means it was locked in before the Great Vowel Shift.

These two simple observations go most of the way towards explaining your mystery.


I'm not sure, but I think "to" and "do" are spelled that way because they are function words. According to Wiktionary, the Middle English ancestors of "do" and "go" were pronounced with /ɔː/ and /oː/, the vowels that became /oʊ̯/ as in "goat" and /uː/ as in "goose". So based on modern English spelling conventions, we could expect "go" to be spelled as is, and "do" to be spelled "doo". Why the shift? I suspect scribes truncated it based on the general notion that function words should be one or two letters long while content words should be three or more (this is also why "are" is spelled with a silent "e" even though it's pronounced like "start" and not like "square").

While it would be naive to believe English spelling represents English pronunciation, there are well enforced rules that govern their relationship, and ambiguities almost always have reasons behind them. I assume it was about these reasons that the OP wanted to learn when they asked the question.


Because the English language has co-opted words from many languages, and then corrupted/changed them over time we have a variety of pronunciation and spelling rules...which are not inflexible (compare the pronunciation of words by an Essex native with that of a Geordie, for example)

There are general guidelines which do broadly work - as long as you know or can guess the origin of a word. Did it come from a Latin root, or one of the Germanic languages, or Norse etc.?

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    "Go" and "do" both come from the same source language.
    – herisson
    Commented Feb 16, 2016 at 3:48

The original pronunciation of the word go was "goo", so that it rhymed with "too".

The following text is from the book "A wife for a month" printed in London in 1717:

Since I am not an expert in the history of the English language, I cannot tell you why the pronunciation has changed from "goo" to "go".

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    Are you sure the pronunciation hasn't changed from "toe" to "too"? Commented Oct 18, 2019 at 23:45
  • Yes, I am sure. In the preface of "The Royal dictionary Abridged" by Mr. Abel Boyer from 1751 it says that the diphthong OO sounds like the french diphthong OU. Commented Oct 24, 2019 at 21:37
  • On the other hand, that poem rhymes feast and guest, as well as shall and all. These words don't rhyme today, either. Why do you think too and go rhymed in the poem? Commented Oct 24, 2019 at 21:50
  • The words "too" and "go" rhymed in the poem for the same reason "feast" and "guest" rhymed in the poem. Also, the words "shall" and "all" rhymed in the poem (the latter sounded like the former and not vice versa). There are many books that describe how English words were pronounced in the past. You can read them. Commented Oct 24, 2019 at 22:40
  • If there are so many books that describe how English words were pronounced in the past, why don't you read them and include some supporting evidence from them in your answer, rather than just citing a poem that has two other near-rhymes in it. Commented Oct 25, 2019 at 15:01

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