Not attested in OED.

• 12.012 or dungeon-hall of the ancient dwarves

This is not a word in OED.

• 12.069 That is the effect that dragon-talk has

It’s not an OED word, so we’re calling it a JRRT word.

• 12.064 of coming under the dragon-spell.

I do not find “dragonslay”, “dragon-slay”, “dragonslayer”, “dragon-slayer”, “dragonslayings,” or “dragon-slayings” anywhere in the most common 100,000 words of the Project Gutenberg corpus!  I will double check, as this is a quite unexpected finding.  Neither is it as a single word (even a two-word single entry) in the OED.

• 12.090 and they all began discussing dragon-slayings historical,
• 15.056 as the dragon-slayer,

Much turns on this concept in the novel… but it is named only once, an original JRRT word.

• 19.044 he fell under the dragon-sickness,

This word is not attested in OED.

• 14.027 Bard the Dragon-shooter of the line of Girion!

There are night-noises in the OED, but no dragon-noises.

• 13.029 and still there were no dragon-noises,

This word is nowhere in OED.

• 10.007 under the shadow of the distant dragon-mountain.

In this case it is lore about dragons, not lore known to dragons.  This word is not attested in any form as a single word in OED.

• 12.046 in dragon-lore as all that,

Although every dragon needs a proper hoard, considering it one word is not attested . in OED.

• 12.015 and sing of dragon-hoards before,