Ough is a four-letter sequence, a tetragraph, used in English orthography and notorious for its unpredictable pronunciation. It has at least eight pronunciations in North American English and nine in British English, and no discernable patterns for choosing among them.
In Middle English, ough was regularly pronounced with a back rounded vowel and a velar fricative (e.g., [oːx], [oːɣ], [uːx], or [uːɣ]).
|//||Brough, chough, enough, Hough, rough, slough (see below), sough, tough||Rhymes with puff. Sough is also pronounced //.|
|//||cough, trough||Rhymes with off. Trough is pronounced // (troth) by some speakers of American English, and a baker's trough is also pronounced //.|
|//||bough, doughty, drought, plough, slough (see below), Slough, sough||Rhymes with how, cow. Sough is also pronounced //.|
|//||although, dough, furlough, though||Rhymes with toe, no.|
|//||bought, brought, dreadnought, fought, nought, ought, sought, thought, wrought||Regularly so used before //, except in drought // and doughty //. Rhymes with caught. In American English dialects exhibiting the cot-caught merger, this is realized as // or //.|
|//||brougham, slough (see below), through||Rhymes with true.|
|//||borough, thorough, Willoughby||Pronounced // in American English, except when destressed by a following syllable in many dialects, as in thoroughly and Willoughby.|
|//, //||hiccough||Variant spelling of the more common hiccup.|
|//||Greenough||Pronounced // as the name of a river in Western Australia. As a surname, it is usually pronounced //.|
|//||Clough, hough, lough, turlough||Hough has been more commonly spelled hock from the 20th century onwards. Lough (an Irish cognate of Scots loch) and (tur)lough are also pronounced //.|
|//||lough, turlough||Both are also pronounced //.|
|//||Ough's Road, Port Hope, ON, Canada||Rhymes with "stops."|
"Slough" has three pronunciations, depending on its meaning:
The town of Slough in the Thames Valley of England is //.
An example sentence using the nine pronunciations commonly found in modern usage (and excluding hough, which is now a rarely used spelling) is, "The wind was rough along the lough as the ploughman fought through the snow, and though he hiccoughed and coughed, his work was thorough."
Another, slightly shorter example would be, "The rough, dough-faced ploughman fought through the borough to the lough, hiccoughing and coughing."
Other pronunciations can be found in proper nouns, many of which are of Celtic origin (Irish, Scottish, or Welsh) rather than English. For example, ough can represent // in the surname Coughlin, // in Ayscough, and // in the name Colcolough (//) in Virginia.
The two occurrences of ⟨ough⟩ in the English place name Loughborough are pronounced differently, resulting in //. Additionally, three parishes of Milton Keynes—Woughton //, Loughton // and Broughton //—all have different pronunciations of the combination.
Tough, though, through and thorough are formed by adding another letter each time, yet none of them rhyme.
Some humorous verses have been written to illustrate this seeming incongruity:
Because of the unpredictability of the combination, many English spelling reformers have proposed replacing it with more phonetic combinations, some of which have caught on in varying degrees of formal and informal success. Generally, spelling reforms have been more widely accepted in the United States and less so in other English-speaking areas. One problem is that a pronunciation with the velar fricative is still found locally in parts of North-East Scotland, where, for example, trough is pronounced //.
In April 1984, at its yearly meeting, the Simplified Spelling Society adopted the following reform as its house style:
In early colonial America, John Smith used the spelling raugroughcum for the animal that is today known as the raccoon. This was a new animal to the explorers and, alongside the tribal name Quiyoughcohannock, shows that the ough combination was still being used to coin new words in early colonial America. Another placename is Youghiogheny, which begins with //.
In the UK, the word dough can also be pronounced //, a pronunciation remembered in the spelling of the word duffpudding. Likewise, the word enough can be pronounced // or // and the spelling enow is an acceptable dialect or poetic spelling (e.g. "And Wilderness is Paradise enow.").
The following spellings are generally considered unacceptable in other areas, but are standard in the United States:
However, all of these are considered unacceptable in written British English and formal American English, except in the most casual and informal forms of textual conversation.
⟨augh⟩ is orthographically rather similar to ⟨ough⟩, but admits much less pronunciation variation:
The similar ⟨ow⟩ yields at least four standard pronunciations, although one is only found in a word derived from a proper name:
Dialectal forms also render pronunciations such as fella //, tomorra // for fellow //, tomorrow //, and winder //, yeller // for window //, yellow //.
A comparable group is ⟨omb⟩, which differs however in that, unlike ⟨ough⟩, it does not ever represent a single phoneme. ⟨omb⟩ can be pronounced in at least five ways:
When a syllable is added after the ⟨omb⟩, the ⟨b⟩ is often (but not always) pronounced, resulting in a total of at least eight pronunciations of ⟨omb⟩:
—but not, for example, in bomber, comber, entombing, etc.
The group ⟨oth⟩ also has a wide variety of pronunciations, in part because of the two phonemes (// and //) represented by English ⟨th⟩. Here are seven different pronunciations:
The group ⟨ong⟩ has at least nine pronunciations, though unlike with ⟨ough⟩ or ⟨omb⟩, context often suggests the correct pronunciation: