The Great Vowel Shift

OK, enough biblical references, back to English history...

It's hard to imagine a professor coining the term 'great vowel shift' because a) it sounds awful, and b) it doesn't give you any indication of what he's talking about.  

English was originally a West Germanic language, brought to the islands by the Anglo-Saxons, where it was mixed with Norse (from the Vikings) and Celtic (from the Picts, as the Scots were then called) to become "Old English."  Here is an example, from Beowulf:

Hwæt! We Gardena         in geardagum,
þeodcyninga,         þrym gefrunon,
hu ða æþelingas         ellen fremedon.
Oft Scyld Scefing         sceaþena þreatum,

Translation:

LO, praise of the prowess of people-kings
of spear-armed Danes, in days long sped,
we have heard, and what honor the athelings won!
Oft Scyld the Scefing from squadroned foes,

In 1066, William the Conqueror brought over French (from the Normans) and Latin (from the church) to create "Middle English."  Here is an example, from the Cantebury Tales:

Whan that Aprill, with his shoures soote
The droghte of March hath perced to the roote
And bathed every veyne in swich licour,
Of which vertu engendred is the flour;

Translation:

When in April the sweet showers fall
That pierce March's drought to the root and all
And bathed every vein in liquor that has power
To generate therein and sire the flower;

Then, in the south of England between1450 and 1550, long vowels moved up and, even more confusing, became short.  

There are many theories for the Great Vowel Shift, ranging from a rising middle class to the to the Black Death.  Some say it was to sound more French; others say it was to distance themselves from the French (with whom they were at war for most of this period).  Whatever the cause, the result was that "Long a" changed from "father" to "ape," "long e" from "shape" to "sheep," "long i" from "machine" to "ice," "long o" from "tool" to "goal," and "long u" from "rude" to "use."

To understand where they went, say "long e" (as in "beet"), then "long o" (as in "boat"), and feel your tongue move from front to back. The long vowels all moved up, like in a chain: /long a/-->/long e/-->/long i/--/aj/ (as in "eye") and /long o/ -->/long u/ -->/aw/ (as in "eight")

They also became short, so while in In Latin (and Middle English and most Romance languages), "long e" "they" is twice as long as "short e" "set," in Modern English "long e" "seat" is the same length as "short e" "set."  So while all other languages different long and short vowels by length, we separate them by sound, which is stupid. And while other languages use dipthongs to represent different pronunciations, we use things like "silent e" to change a vowel from short ("rat") to long ("rate").

(By the way, Finnish doesn't have two vowel lengths, it has five: short and long stressed, short and long unstressed, and a short vowel immediately preceded by a stressed short vowel, called a "half vowel.")

Now that would have all been fine -- languages are constantly in flux -- except the printing press was introduced in England around 1470, and dictionaries did not appear until 1604.  In between, spelling was phonetic -- you wrote it like you pronounced it -- which meant that written English captured every single one of these changes!  Spellings that made sense according to Middle English pronunciation now look retarded in Modern English!

While we're on the subject, you may also be interested to know the last great change on the English language was intententionally inflicted by one man: Noah Webster. Starting with grammar school "spellers" in 1786, and continuing with his dictionary in 1806, he single-handedly established 'American English.'