It's the oldest surviving song in English to which we have both words and tune, an earthy and exuberant hymn to spring. It's also a delight.

Sumer Is Icumen In

Sumer is icumen in;

lhude sing, cuckoo.

Groweth sede and bloweth mede,

and springth the wode nu;

sing cuckoo.

Yowe bleteth ofter lomb,

lhuth ofter calve cu;

bullock sterteh,

bucke verteth,

murie sing, cuckoo.

Sing cuckoo, well singst thou, cuckoo:

ne swic the nevere nu.

For something written circa 1240, it's amazing how readily comprehensible it is. A few cribs:

lhude: loud   bloweth mede: meadow blooms   yowe bleteth: ewe bleats   lhuth: lows   cu: cow    sterteth: starts [i.e. jumps]   murie: merry   ne swic the nevere nu: don't you ever stop, now

You've got to love bucke verteth. The buck in question here is specifically a he-goat. Squeamish commentators gloss verteth as “jumps,” presumably in tandem with the starting bullock of the previous line. More honestly—but still, to my mind, over-delicately—The Oxford Book of English Poetry translates, “breaks wind.”

The he-goat farts. Yes siree, must be spring.

Scholars trying to reconstruct Proto-Indo-European society from the surviving vocabulary were stymied left and right by lack of information. What we do know about the ancient Indo-Europeans is that they had two words for breaking wind: one for breaking wind quietly, the other for breaking wind loudly. This latter is the ancestor of our word fart. The ancestors were earthy people.

It took a hunter to explain to me why farting goats would be a sign of spring. “Oh, deer are like that too,” he said. “After eating nothing but dry stuff all winter, they all get diarrhea in the spring when there are finally fresh greens to eat.”

Those earthy ancestors.

Ezra Pound—poet, pagan, anti-Semite—has left an amusingly modern companion piece to Sumer Is Icumen In; two songs for the price of one. Its urban, thoroughly humano-centric perspective contrasts strikingly with (and comments ironically on) the original, which is entirely about the natural world and never mentions people at all (or rather, is itself the human commentary on that which it observes).

Antient Music

Winter is icumen in;

lhude sing, goddam.

Raineth drop and staineth slop,

and how the wind doth ram.

Sing goddam.

Skiddeth bus and sloppeth us,

an ague hath my ham;

freezeth river, turneth liver,

damn you, sing, goddam.

Sing goddam, against the winter’s balm,

lhude sing goddam.

https://www.youtube.com/watch?v=BVdA9t-AOfU