 Sometime before 1969, Tolkien wrote the essay "Of Dwarves and Men", in which he gave detailed consideration to the Dwarves' use of language, that the names given in the stories were of Northern Mannish origin, and Khuzdul being their own secret tongue and the naming of the Seven Houses of the Dwarves.The essay represents the last of Tolkien's writing regarding the Dwarves and was published in volume 12 of "The History of Middle-earth" in 1996.In the last interview before his death, Tolkien, after discussing the nature of Elves, briefly says of his Dwarves