[William Cloud Hicklin]

Oh, certainly Tolkien never could make up his mind. That's rather the point: any discussion about Middle-earth really contains within it the question "when?" The publication of one book plus its cursory revision simply cut through an ongoing development transversely in time. When he wrote The Lord of the Rings T clearly thought the Wood-elves to be Avari; but in the History of Galadriel and Celeborn "They were descended from those of the Teleri who, on the Great Journey, were daunted by the Misty Mountains and lingered in the Vale of Anduin...but they still remembered that they were in origin Eldar."

Yet still at the same time T could give us Mithrellas, an Elf of Lorien who, according to the Appendix A statement that there were only three marriages of Eldar and Edain, by definition could not be Eldarin.

Even that is less solid than it appears; the 1st Edition text has it that there were three marriages "between High Elves and Men" - a statement which was an error when he wrote it because Luthien, however lofty her maternal lineage, was never a High Elf.

Similarly the Silvan tongue: when T wrote the chapter, Frodo simply couldn't understand the Avarin dialect of Lorien. By the Second Edition, a footnote tells us F was listening to Sindarin spoken with a Silvan accent. Two late essays state that A) Thranduil's household spoke Sindarin but not his Silvan-speaking people, and B) Silvan was no longer spoken in Mirkwood/Lorien by the late Third Age. Pick one.