Lady Galadriel has different message for each class, here follow the transcripts. ([1] - combined research, 2010)

Burglar

A great tower in moonlight, a shadow against the sky.

A cell with no escape.

The stairs are watched.

I cannot see how you come to this place, Burglar… nor how you could leave it.

             NOTE: This refers to the events of In the Presence of Saruman(vol. 3, book 4 chapter 20)

Captain

A long vigil, waiting for an ally that does not come.

Your words must inspire, for time passes too slowly behind the walls.

They cannot stand forever, the walls, nor the Men under your command.

The dawn seems far off, Captain; is it your fate to see it?

Champion

A shadow beneath the trees -- it moves without sound.

Might will not avail you. It stalks without mercy, unrelenting.

Someone bellows a challenge, and suddenly a beast is by your side…

Whether this beast be friend or foe, I cannot see. I hope you will know the difference.

Guardian

A crash of thunder, a broken shield.

The wall of spears moves in time to the drum-beat of doom.

A shroud of despair as the great beast descends…

You are a mighty Guardian, but not all friends can be saved.

Hunter

I see great webs strung beneath the trees.

A friend in peril, her life's blood mingling with venom and remorse.

Chattering, evil shapes approach. Your bow longs to sing…

There are too many, Hunter, even should all your arrows find their marks.

NOTE: This refers to the events of Mazog in the Web(vol. 2, book 9 chapter 8)

Lore-master

The prize of knowledge, it waits, ripe for the taking.

A library at the pinnacle of the black spire, secrets untold.

Enemies without, and within…

How far will your heart take you for limitless knowledge, Lore-master?

NOTE: This refers to the events of In the Presence of Saruman(vol. 3, book 4 chapter 20)

Minstrel

Stairs climb unceasingly into the heights.

A city sleeps, its inhabitants gone.

But not all, not yet. Those that remain dream a restless dream…

Will your songs stir them to wakefulness, Minstrel? Is that to be your fate?

Rune-keeper

Runes of power in the darkness.

Secrets unseen for an age.

A blast of warm air, and you turn to stare into yellow eyes…

You speak words of power, but still the eyes stare out of the darkness, unafraid.

Warden

A thundering of hooves shakes the earth.

Black sails fly on a river of dread.

Your foes are everywhere, but you see them not.

Your grief blinds you to them, Warden, and you defy death in its name.