Q: Why do words like “caught,” “ought,” “thought,” “bought,” “naught,” “laugh,” and “should” have endings with no bearing on the way the words sound?
A: I think you’ve asked a much larger and more complicated question than you realize!
Our spelling system began as an attempt to reproduce speech. But because most spellings became fixed centuries ago, they no longer reflect exact pronunciations.
As a result, spelling is about more than pronunciation; it also reflects a word’s meaning and etymology and history. And in the case of English words, their spellings often have very idiosyncratic histories hidden within.
You mention “caught,” “ought” and others. The appearance of “gh” in words like these is annoying to people who’d like to reform English spelling. Many wonder, for example, why “laughter” and “daughter” don’t rhyme. Well, they once did.
“Daughter” has had several pronunciations over the centuries, including DOCH-ter (with the first syllable like the Scottish “loch”), DAFF-ter (rhyming with “laughter’”) and DAW-ter. We know which one survived.
The Middle English letter combination “gh” is now pronounced either as “f” (as in “cough/trough/laugh/enough”) or not at all (“slaughter/daughter/ought/through,” etc.).
The word “night,” to use another example, went through dozens of spellings over 600 years, from nact and nigt and niht, and so on, eventually to “night” around 1300. It’s a cousin not only to the German nacht but probably to the Greek nyktos and the Old Irish innocht, among many others.
The odd-looking consonants in the middle of “night” (as well as “right” and “bright”) were once pronounced with a guttural sound somewhere between the modern “g” and “k.” But though the pronunciation moved on, the spelling remained frozen in time.
You also mention “should,” a word in which the letter “l” looks entirely superfluous. But the “l” in “should” and “would” was once pronounced (as it was in “walk,” “chalk,” “talk,” and other words).
Same goes for the “w” in “sword” and the “b” in “climb.” They were once pronounced. Similarly, the “k” in words like “knife,” “knee,” and “knave” was not originally silent. It was once softly pronounced. But while pronunciation changed, spelling did not.
There are several reasons that English spellings and pronunciations differ so markedly.
Much of our modern spelling had its foundation in the Middle English period (roughly 1100 to 1500). But in the late Middle English and early Modern English period (roughly 1350 to 1550), the pronunciation of vowels underwent a vast upheaval.
Linguists call this the Great Vowel Shift, and it’s too complicated to go into in much detail here. To use one example, before the Great Vowel Shift the word “food” sounded like FODE (rhymes with “road”).
Melinda J. Menzer’s Furman University website can tell you more about the Great Vowel Shift. I’ve also touched on it briefly in a blog item.
While the pronunciations of many words changed dramatically, their spellings remained largely the same. Why? Because printing, which was introduced into England in the late 1400s, helped retain and standardize those older spellings.
Complicating matters even further, the first English printer, William Caxton, employed typesetters from Holland who introduced their own oddities (the “h” in “ghost” is an example, borrowed from Flemish).
In addition, silent letters were introduced into some English words as afterthoughts to underscore their classical origins. This is why “debt” and “doubt” have a “b” (inserted to reflect their Latin ancestors debitum and dubitare).
Sometimes, a letter was erroneously added to reflect an imagined classical root. This is why “island” has an “s” (a mistaken connection to the Latin isola). I’ve written a blog entry about this.
Still other English spellings came about in the Middle Ages when scribes found that the letters “m,” “n,” “u,” and “i” caused readers difficulty because of all those vertical downstrokes of the pen (“m” + “I” was hard to tell from “n” + “u”). So “o” was substituted for “u” in words like “come,” “some,” “monk,” son,” and “wolf.”
Apart from ease of reading, “o” was sometimes swapped for “u” because, as Dennis Freeborn writes in his book From Old English to Standard English, “u was an overused letter. It represented the sound v as well as u, and uu was used for w.”
Another authority, David Crystal, has pointed out that England’s “civil service of French scribes” following the Norman Conquest in the 11th century also influenced the spelling of English words.
Crystal writes in his book The Fight for English that not only did consonants change (the French “qu” replaced the Old English “cw” in words like “queen,” to use just one example), but vowels “were written in a great number of ways.”
“Much of the irregularity of modern English spelling derives from the forcing together of Old English and French systems of spelling in the Middle Ages,” he says.
As you can see, this is a vast subject. In summary, spellings eventually settle into place and become standardized, but pronunciations are more mercurial and likely to change.