TYRN GORTHAD: Thank you, nurse!’ (American text speak). Here, a twisting cave leads to the beginning of the underworld.
H: Nimble Field Marshal gains direction even as all becomes confused here.
ERESTOR: See him before the decay returns; a sibilant is swallowed.
F: Ask Debussy when it sounds like he sings. It might be after noon.
ERIADOR: Thingol’s land is transformed into another, as a fricative element gives way to hesitation in the general turmoil.
L: He’s a lover of confectionery, with only one small exception.
L: Food guilt? It’s confusing when someone lays that on you.
O: His table manners leave much to be desired.
WITHYWINDLE: Shrivel without hesitation, here in France? Decline, after first loss. But on it flows.
SILVERLODE: Fifty pence pieces can really weigh your pockets down, I hear! That considered, on it runs.
H: Here you’ll find a stove with tooth marks in it, they say!
I: Girl traps boy here. Mother too, initially, and first.
P: Here find oriental bread, lose two articles, and meet a physician.
O: Flatulent and sibilant children’s author? (Forget his surname). It's confusing, but perhaps he’s sampled this?
F: Spanish greeting for Balin’s directionless dad; despite the confusion, it’s not that far from where his son lies.
T: Charlatan of a professor – looks peaky after much confusion!
HALFAST: He’s semi-sedentary, with very minimal disturbance.
E: An eternally tough dancer, we hear.
RAUROS: Dark Lord changes direction as he tumbles here.
I: What Drogo might have yelled here, in 2980, had he been a Cockney?
NOB: Does he really ban the use of a certain plosive?
G: To a linguist’s mind, he seems almost to specialise in golden tautology.
TY (Thank you in text speak) + RN (Registered Nurse - American because they're RGN's in Britain (the G is for General)) + GROT for cave ('She took me to her elfin grot' is a line from Keats's 'La Belle Dame Sans Merci') + HAD(ES).
SILVERLODE - quite correct, SILVER being a word used to collectively refer to silver-coloured coins, (50p, 20p, 10p, 5p). Do you have that term in Canada and/or the USA, G55 and Urwen? The copper-coloured coins (1p and 2p, and ha'pennies when I were a lass) are referred to as coppers.
You're close on the last clue, Huey. Note the 'almost.' The two words that form the clue are in the same semantic field, but in grammatical terms they don't mean exactly the same thing. They are from different word classes. EDIT: And because I'm feeling generous, OR is one of them.
Knock down my clues, indeed! How VERY dare they! 