Hopkins puts the reader between two noises. The sea sounds in one ear and a skylark in the other, and the sonnet first lets us hear them before it turns on the human world that can't match them. The octave is pure listening. The sestet is judgment: the sea and the lark are "pure", while "we, life's pride and cared-for crown" are falling apart.
The sea comes first, and it is physical. The two noises "trench" into the ears as if gouged out of them, and the tide "ramps against the shore", rearing up like an animal. Hopkins lets the sound of the words imitate the sound of the water. "With a flood or a fall, low lull-off or all roar" slides from the soft liquid *l*'s of "lull" to the open boom of "all roar", so the line swells and ebbs as it is read. The sea is also timeless: it will go on "while moon shall wear and wend", a phrase that ties the tide to the moon's slow, repeated journey.
The lark is a different kind of marvel. Where the sea is heavy and constant, the bird is quick and spiralling. Hopkins turns its song into thread: a "re-winded new-skeinèd score" that unwinds "in crisps of curl off wild winch whirl". The music is both a skein of yarn and a musical score, and the hard *c* and *k* sounds of "crisps of curl" give the notes a bright, brittle edge. "Rash-fresh" is a typical Hopkins compression. The song is impulsive and also newly made, though the bird has surely sung it a thousand times. The lark then "pours and pelts" music until "none 's to spill nor spend". Its generosity is total, and it holds nothing back.
The turn comes with the ninth line: "How these two shame this shallow and frail town!" The word "shame" is the hinge. The sea and the lark are not simply pleasant. They reproach us. Against them, our own era is "sordid" and "turbid", a word that suggests muddy, clouded water, so even the insult borrows its imagery from the natural world. The bitter irony is in "life's pride and cared-for crown". Humans have given themselves the grandest title in creation, and the poem then takes it away. We have "lost that cheer and charm of earth's past prime".
The last two lines are the most unsettling. "Our make and making break, are breaking, down" is deliberately ambiguous. "Make" can mean our physical and moral constitution, and "making" can mean everything we manufacture and build. The verbs shift from "break" to "are breaking", which makes the collapse feel ongoing and not finished. Then the poem ends on a bleak symmetry: we drain "to man's last dust" and "towards man's first slime". The poem sets the end of humanity beside its beginning. Judging by the imagery, decline is a return to the starting point, a circle that closes on the lowest matter, which is a far cry from "crown".
The form carries the argument. It is a sonnet, and the octave rhymes ABBA ABBA, with "end" and "wend" bracketing "shore" and "roar". The sestet then switches to alternating rhymes (town, time, crown, prime, down, slime). In the octave the rhymes enclose each other, almost like waves folding back, and in the sestet they march forward, which suits the sense of something running downhill. The sentence in the sestet also spills across the stanza gap, from "crown," into "Have lost", just as the pride of the crown tips into loss.
Rhythm is where Hopkins is most himself. The lines lean on stress rather than on neat syllable-counting, and phrases like "wild winch whirl" pile up beats so the tongue has to slow down and work. The long, indented lines stretch to hold the sea and the lark, and the poem is so packed with alliteration and inner rhyme that it asks to be read aloud.
The poem matters because it makes its argument through sound. Hopkins doesn't merely tell us that the natural world is purer than the modern one. He fills our ears with it, then holds up the human world for comparison. The result is both a nature poem and a warning, and the warning lands harder because the music has made us love what we are being told we are losing.