La Belle Dame Sans Merci The Supernatural Quotes

The lady speaks in a strange language. Is it actually a different language, or does she just have an accent? Or is she speaking a different version of English (perhaps a more everyday, common language) from what the upper-class knight is used to? It's unclear.

The lady takes the knight to her "elfin," or elfish cave. Was it filled with obvious signs of magic or witchcraft? How does he know that it's "elfin," and not just a cave where this lady lives? We don't get any of the details, so it's hard to tell.