I will translate anything into Latin.

[TheYell]

Not quite as snappy in Latin, is it? By the way, both "elf" and "dwarf" are cruxes in Latin; neither word has an exact equivalent. The usual gloss of Old English ælf is nympha, a word that is always feminine in meaning as in grammatical gender (when, indeed, ælf is not used to translate dæmon or diabolus). Latin nanus is never used to denote a supernatural being.

Since Tolkien was referring to populations largely defined by language, you might want to follow the classical manner of referring to the barbarian tribes - "the people who call themselves Eledhrim" and "the people who call themselves Khazad", Romanizing their tribe names as usual.