Eldorion wrote:
I was never actually clear if in the book it is Frodo or the
Ring itself speaking to Gollum. The passage describes Frodo as "a figure robed in white, but at its breast it held a wheel of fire. Out of the fire there spoke a commanding voice...." (
RotK, Mount Doom). That's not really conclusive one way or the other for me.
This has been said a number of times in this thread, but it was the divine intervention of Eru that pushed Gollum over the book, cf. Letter 182.
Also, welcome to the forum Bookworm!

This quote from the book clearly shows that the power of the ring is at work here. The voice speaking, I think, must be Frodo's. At least, if the ring has any "will of its own" (which clearly it does) then it would have been far better off in Gollum's possession (who wanted to save it) than Frodo's (who wanted to destroy it). Of course, it is debatable whether or not the ring has any sense of what its holder may have in mind for it. It certainly is capable of discerning when its holder is of no further use for it (e.g. when it "abandoned" Gollum in favor of Bilbo in The Hobbit).
Still, I may be reading more into it than is really there.
This is one of the really great things about LOTR. There is a lot of depth to the story.