I think they just use The Ancient Language as their language. They also speak English.
Elven names are in the language Tengwar, which was invented by Tolkien. But some of the elven names do have an english tone to them. Good examples of this are names like Arven or Legolass.
The "name" of the elven celebration in Eldest?The English name for it would be the Blood-Oath Celebration. The Elven name for it would be Agaetí Blödhren.
FeanorFingolfinArwenGildorGlorfindelElladanElrohirCirdanLegolasEolElweThingolFinarfinTurgonAredhelFinrodAegnorAmrosAmrodGwindorFinweGaladrielGelmirGwindorIndisIngweCurufinCelebrimboretc.
Finnish is the language spoken in Finland and it is also the language that the Elven language in Tolkien is based on.
I know the name, but, it is a secret. I am the author of The Forest Emerald, and I can not tell you. I will give you a hint though, it is three letters. -Silver Shadowslayer
brisingr means fire in the elven toungue or the ancient language
Mirkwood.
The name of the city is Rivendell.
The Elven King
There have not been any published books that have used Tolkien's elven language. There are numerous 'fan' written stories that have used Elvish and some attempts have been made to write entirely in elvish, but none have been made available commercially.
umm..... 11 is spelt eleven, elven means, like, 'elvish, of the elves'. Anyways, 111,111, I think, though I'm not sure what 'elven lac' is, so I didn't write it.
The Dwarves never use their own language (Khuzdul) when writing down something. They always use the Common Speech or some Elven language.