A Tolkien Dictionary created by John Ireland may be useful for those interested in Middle-earth etymology. Ireland's sources are the indexes of The Lord of the Rings and The Silmarillion.
Also included on the bottom of the page is a link to a Tolkien Language List though it appears you may have to be a member of something (not quite clear as to what) in order to access the information. If anyone has information on what the List has to offer and to what you must join to access it please feel free to contact me at email@example.com. I will pass any information along in this blog.
A Tolkien Dictionary