The Writer's Almanac with Garrison Keillor

Today marks the autumnal equinox in the Northern Hemisphere, the first day of fall and the point in which the Sun is directly above the equator and the hours of day and night are nearly equal. It occurs at precisely 10:49 a.m., Eastern Daylight Time. In the Southern Hemisphere, today marks the vernal equinox, the first day of spring.

As poet Sarah Morgan Bryan Piatt wrote: "It is the summer's great last heat, / It is the fall's first chill: they meet."

It's the anniversary of the Norman Conquest of 1066. It was this week that William the Conqueror of Normandy first arrived on British soil. The French-speaking Normans eventually defeated Old English-speaking Saxons at the Battle of Hastings on October 14, 1066 — which had a larger and more pronounced effect on the development of the English language than any other event in history.

Norman French replaced the Germanic-based Anglo-Saxon as the official, administrative, and ceremonial language, and Anglo-Saxon was demoted to everyday, common use. The sturdy English cow, calf, and sheep on the hoof became French once they were on the plate: beef (from boeuf), veal (veel), and mutton (mouton). The word vellum, for a type of parchment made of calfskin, also comes from the French word for calf. In all, some 10,000 French words were adopted into the English language, and within the course of a few centuries, English went from being a strictly Germanic language to one infused with a large Latinate vocabulary, which came via French.

The Normans of course also imposed their ideas and practices of governing on their conquered English subjects, and our vocabulary still reflects a huge number of French-based words. Government is a word of French origin that came in during Middle English. The Old French word is governer from Latin "to steer" or "to rule."

For many years, English-speaking subjects took allegiance to the royal crown. Allegiance is a distinctly Anglo-Norman word — it's a variation of the Old French ligeance, from a Latin word describing foreign serfs who were allowed to settle on Roman land and till the soil.

Subject, no surprise, was a word introduced by the Norman invaders, and when it first came into Middle English from Old French (sujet, "brought under"), the word meant "a person owing obedience."

Yet the conquered English subjects continued to swear allegiance to the king. The French-speaking Norman leader of the invaders, William the Conqueror, actually tried in his middle age to learn to speak English, the tongue of his newly conquered subjects. But from the invasion, English gained several synonyms of French origin that meant, essentially, kinglike or kingly. These include royal, regal, and sovereign. Royalty developed in the late Middle Ages to include a sense of "right to ownership" over minerals, which in the mid-1800s began to also apply to payment given by a mineral harvester to the person who owned the land from which the mineral came. Later, royalties applied to the sales of copyrighted materials.

From the Norman Conquest came the Anglo-Norman French word corune, from Old French coroner, ultimately from Greek for "circle, ring." It formed the basis not only of the kingly crown, but also of corolla — the inner ring of petals in a flower — and corollary, coronary, coronation, and coroner — who in Norman times, as an officer of the crown, was appointed to investigate any seemingly unnatural deaths of members of the ruling class.

Words from the Anglo-Norman legal system also form the primary basis for the vocabulary of our modern legal system. A defendant is summoned to court, from the Old French cort, from the Latin word for yard. If it's a civil affair, one might hope that all people "present at court" (the original meaning of courtier) will be courteous, which originally meant "having manners fit for a royal court." A complaint is filed by the plaintiff, from the Old French word plaintive — a "lamentation" — which is itself derived from a Latin word, planctus, meaning "beating of the breast."