The -ough problem: seven sounds, one spelling
Seven ways to say four letters. The reason is not that English is lawless — the spelling was fixed while the sounds were still moving.
By Dilnoza Yusufova · Linguist
Read these aloud, in order: through, though, thought, tough, cough, bough, thorough. Seven words, the same four letters at the end, and seven different sounds — one of which is not even a sound but the absence of one. No other spelling in English behaves this badly, and the usual explanation, that English is simply irregular, explains nothing. The letters were once perfectly regular. What changed is everything around them.
In short
- -ough has seven standard pronunciations, and nothing in the spelling tells you which one you are looking at.
- The letters once stood for a real sound, /x/, that later vanished or turned into /f/.
- There is no rule to learn. There is a list of about twenty words, and it is short enough to learn whole.
The seven
| Sound | Words | Rhymes with |
|---|---|---|
| /uː/ | through | blue |
| /əʊ/ | though, dough, although | go |
| /ɔː/ | thought, bought, ought, fought, brought | sort |
| /ʌf/ | tough, rough, enough | stuff |
| /ɒf/ | cough, trough | off |
| /aʊ/ | bough, plough, drought | now |
| /ə/ | thorough, borough (British) | the end of sofa |
Those are the standard seven. Add hiccough — a spelling invented in the seventeenth century for a word that is really hiccup — and you have an eighth, though nobody counts it.
One sub-group comes close to a rule: -ought is /ɔːt/ in thought, bought, brought, fought, ought, sought and nought.
One common word breaks it, and it is in the table above: drought is /draʊt/. So even the best pattern in this group has an exception you have to know in advance.
The sound that disappeared
The gh was not decoration. In Old and Middle English it stood for a consonant that English has since lost: a rasping sound made at the back of the mouth, written /x/, and still alive in German Nacht and Scots loch. Night was /nixt/. Though ended in it. Tough ended in a version of it made further forward in the mouth.
Then, between roughly 1400 and 1600, that consonant went. Not evenly, and not everywhere at once. In most words it fell silent and left the preceding vowel to lengthen or shift. In a small group, the back-of-the-mouth friction moved forward to the lip and became /f/ — which is how tough, rough, enough, cough and trough ended up where they are.
- night, light, brightthe sound fell silent and the vowel took over
- tough, rough, enoughthe friction moved forward and became /f/
- through, thoughthe sound fell silent, and the vowels went their own ways
Why the spelling did not follow
Because of the timing. William Caxton set up his press at Westminster in 1476, in the middle of all this, and printers needed a single spelling for each word long before the pronunciation had finished moving. They took the written forms they had, which recorded the older sound, and fixed them in type.
Within a century the printed spelling was everywhere and the sound it recorded was gone from most words. The -ough group is the clearest surviving evidence of that mismatch: not seven spellings for one sound, which would be ordinary, but one spelling for seven sounds, which is what happens when a page stops moving and a language does not.
The pair that matters most
Of all of these, one pair does real damage: though and through. They differ by a single letter, they share no sound at all, and both are common enough to appear in the same paragraph.
though /ðəʊ/ through /θruː/ thorough /ˈθʌrə/ thought /θɔːt/
Though begins with the voiced /ð/ of this and rhymes with go. Through begins with the voiceless /θ/ of think and rhymes with blue. Thorough has two syllables and belongs to neither. Learners who treat the three as variants of one word produce sentences that cannot be repaired by context.
Mistakes to avoid
Wrong: thought — /θaʊt/ correct: thought — /θɔːt/
The -ough of thought is the long vowel of sort, not the diphthong of now. Compare bought, ought, fought: the same five letters, the same sound.
Wrong: though — /θruː/ correct: though — /ðəʊ/
Two different words, one letter apart. Though has the voiced /ð/ of this and rhymes with go; through has /θ/ and rhymes with blue.
Wrong: enough — /ɪˈnaʊ/ correct: enough — /ɪˈnʌf/
In enough, tough and rough, the gh is pronounced /f/. In most other -ough words it is silent.
Wrong: thorough — /θruː/ correct: thorough — /ˈθʌrə/ (British), /ˈθʌroʊ/ (American)
Thorough has two syllables. Reading it as through is the single most common mistake with this group, and it changes the word entirely.
Check yourself
Trust your ear
4 pairs
Four questions. Each one is about sound, not spelling — say the word out loud before you answer.
Which word rhymes with tough?
**Tough** is /tʌf/: the **gh** is /f/ and the vowel is the short /ʌ/ of **cup**.
Which word rhymes with though?
**Though** is /ðəʊ/. Its near-twin **through** is /θruː/, which is the one that rhymes with **blue**.
Which word rhymes with cough?
**Cough** is /kɒf/ — the only common companion of **trough** in this group.
How many syllables in thorough?
/ˈθʌrə/ in British English, /ˈθʌroʊ/ in American. It is not a longer spelling of **through**.
Keep this
- Seven sounds, about twenty common words. Learn the list: the only near-rule is -ought as /ɔːt/, and drought breaks even that.
- gh is /f/ in tough, rough, enough, cough and trough, and silent in the rest.
- Watch the pair though and through: one letter apart and nothing alike.
Questions readers ask
Is there really no rule at all?
Almost none. The best sub-pattern is -ought as /ɔːt/ — thought, bought, brought, fought, ought, sought, nought — and even that has drought /draʊt/ against it. Everything else has to be learned word by word.
What about hiccough?
An eighth pronunciation, and an accident. The word is hiccup; the spelling hiccough was invented in the seventeenth century by writers who guessed it was related to cough. It is still pronounced /ˈhɪkʌp/.
Do Americans say these differently?
A few. Borough and thorough end in /oʊ/ in American English rather than /ə/, and trough is usually /trɔːf/. The seven-way split itself is the same on both sides.
Sources
- Crystal, D. Spell It Out: The Singular Story of English Spelling. London: Profile Books, 2012.
- Upward, C., and Davidson, G. The History of English Spelling. Chichester: Wiley-Blackwell, 2011.
- Wells, J. C. Longman Pronunciation Dictionary. 3rd ed. Harlow: Pearson Longman, 2008.