Fantasy Books/Movies: Why are elves represented so differently?

[pastor's wife]

In most fantasy books, if the author writes about a dwarf or a troll, you know what kind of creature you will get. Dragons may be good or evil, but they're still basically the same kind of creature. A basilisk is a basilisk, a vampire is a vampire (and they're NOT supposed to sparkle btw), goblins are goblins, giants are giants.

There is one character though that seems to be portrayed in very different ways and that is elves. In Tolkien, elves are human-like and noble and awe-inspiring. In other books, elves are tiny, spritely, mischevious and silly. Fairies are similar: are they tiny flitting creatures like butterflies or are the the fair folk, beautiful and deadly?

I just thought it was interesting. Any thoughts?

[elfdream]

Tolkien was trying to create a mythology for England. In other mythological traditions the 'gods' were involved in human life. Some civilizations were thought to be descended from them. While Tolkien was careful to not make the elves divine he did give them the characteristics of what he thought would be unfallen immortal beings who guided and taught mankind. They were not really angels either. They were like humans, only better.
Why he choose to call them elves I do not know.