Why does “ough” have so many sounds?

Seven sounds, one spelling

Say these words out loud: rough, cough, though, through, thought, plough, thorough. They all have ough in them, but it sounds different in each one.

The table uses the British way of saying each word, from the Cambridge Dictionary. All the words in it are examples from England's national curriculum.

When gh was a sound

Hundreds of years ago, the gh in these words was not silent. It stood for a breathy sound, a bit like the ch in the Scottish word loch. So rough did not end in an “f” sound. It ended in that breathy sound.

Then the sound changed, in two ways

Slowly, people stopped saying the breathy sound. But it did not change in the same way in every word. In some words, it faded away to nothing, as in though, through and bought. In others, it turned into an “f” sound, as in rough, tough and cough.

In standard English, the old breathy sound lasted until about 1600. Then the sounds we use today took over.

For a while, words had more than one sound

For a long time, many of these words could be said in more than one way. In 1634, Charles Butler wrote a grammar book. In it, he said that laugh, cough, tough and enough “commonly sound like laf, cof, tuf, enuf”.

Some people put an “f” on words we now say without one. A letter from 1465 spells through as thorf. In 1701, a writer said that some people say bought as “boft”. And in a story from the 1740s, a maid says thof for though.

In standard English, these words settled on different sounds. The pattern can look like luck. Laughter and slaughter are both spelt with gh, but only laughter has an “f”. Henry Wyld wrote books on the history of English. In 1920, he said he could find no real reason for that.

Why didn't the spelling change?

Before printing, people spelt words in all sorts of ways. One study of old writing found about 500 different spellings of through!

In the late 1400s, printers began to print books in English. Bit by bit, spelling settled down. By the middle of the 1600s, nearly all printed words were spelt as they are today.

But this was just when the sounds of English were changing a lot. The vowels were changing, and so was the gh. So printing kept an old way of spelling these words, while the way people said them moved on. That is how ough ended up with so many sounds.

Through and thorough

Through and thorough were once the same word. They only split into two words later on. That's why thorough is about going all the way through something. A thorough wash gets you clean all over.

Two odd ones out

Some people spell hiccup as hiccough. That spelling came from people wrongly linking the word with cough. But it is still said “hiccup”, so here ough makes an “up” sound.

In Ireland, a lake can be called a lough. It comes from the same Irish and Gaelic word as loch. The Cambridge Dictionary gives two ways to say it. One sounds like lock. The other ends in the breathy ch of loch, so this ough can still end in that old sound.

Try these out loud

Each of these has ough more than once, with different sounds. Can you read them without a slip?

• Though the dough was tough, we ate it all.
• I thought I had brought enough.
• The plough went through the rough ground.
• The pig gave a cough and a thorough sniff.

Questions people ask

How many ways can you say ough?

In British English, at least seven in everyday words. Count rarer words like hiccough and lough, and you get more. Other accents can sort the words in a different way. In American English, for example, borough ends like go.

Do children learn ough words at school?

In England, yes. The national curriculum includes words with ough in its spelling work for Years 5 and 6. Its guidance calls ough “one of the trickiest spellings in English”.

Is it plough or plow?

Both. The Cambridge Dictionary gives plough as the British spelling and plow as the American one. Both are said the same way, to rhyme with cow.