This article was first published on June 9, 2015, on The Editors’ Weekly, the blog of Editors Canada (the Editors’ Association of Canada)
You want some tough spelling for an English learner to plough through? Head to ough. There are six different ways it can be said at the end of a word, as in plough, through, dough, enough, cough and (for those who spell it that way) hiccough. (Never mind the versions with another letter after it!)
Nearly all of the ough words trace back to the same final consonant in Old English (what our language was from the seventh to 11th centuries), but to several different vowels — vowels that do not match tidily to modern sounds.
What was the Old English final consonant? It was g, also written as h. In certain places, the Old English g softened to a fricative and, at the end of a word, tended to become voiceless. So, in different texts, you could see g or h both standing for the “h” sound. In Middle English (what we spoke from the 11th through 15th centuries), the fricative version of g was written as ȝ, a letter called yogh (which, by the way, is the only current English word ending in ogh).
Over time we stopped making that sound and replaced it with other sounds or with nothing … but we kept writing it. However, when we got printing presses, the type sets we bought from Europe had no yogh in them. So we got gh instead (just as the lovely letter þ was replaced with th).
What were all those vowels that ended up as ou in ough? Some were o’s, short or long; some were u’s; occasionally there was a long a. In the normal course of things, the modern English descendants of those sounds (after a millennium of mutation) are as follows: long á became “long o,” so hám became home; short o became “short o,” hardly changed in pot and bottom; long ó became “long oo,” so fóda became food; long ú became ow or ou, with mús becoming mouse and dún becoming down; and short u ended up sometimes as in put and sometimes as in putt (which sound the same in certain dialects).
But the ough words are not the normal course of things. There was this velar fricative after the vowel, and in Middle English it gradually weakened and caused rounding of the lips (velar fricatives tend to do this because they make the sound contrast more). So plog became our word plough, and slog became the rhyming slough, because they had the vowel in “pot” plus a “w” sound. For some reason, bóg took this course too and became bough. From dáh, which naturally evolved towards the vowel in home, we got dough. The history of burg to borough and þuruh to thorough is more chaotic — in some modern English dialects, the final vowel is like “uh.” Meanwhile, we got through from þurg because it made it to Middle English with the u before the r, so it kept the “oo” sound, and then the u and r swapped places while the final fricative stopped being said.
And then there are the ones that kept a stronger stressed “wh” sound in Middle English — or that only appeared in the language then — such as the Old English genóg, tóh and ruh and the Middle English slohu and coȝ. The strong “wh” sound at the end was dominant enough that the vowel was shortened to the one we hear in “book” (except in coȝ, which had a short o with no u influence). But then we strengthened the “wh” sound at the end of words to make it “f.” And so we got enough, tough, rough, slough and cough.
Oh, and what about hiccough? That’s due to pseudo-etymological mischief. The word was hicke up or hikup — readily reflected today as hiccup — but some silly fellows decided it must come from cough and so, because they wanted words to show where they came from (that classist obsession with pedigree), they started respelling it. It’s a mere parvenu, a poseur. A hiccup.