I think that Plant was replicating the same technique that Tolkien does. Tolkien's story is based on languages. He draws concepts, characters and names from Norse and Celtic myths. There is a reason the Dwarves names all sound the same. Led Zeppelin's song does the same thing. It pulls from several mythologies to discuss the ultimate battle of good and evil. Plant obviously considers Tolkien's story on par with other mythologies that explain good and evil.
I think that Plant was replicating the same technique that Tolkien does. Tolkien's story is based on languages. He draws concepts, characters and names from Norse and Celtic myths. There is a reason the Dwarves names all sound the same. Led Zeppelin's song does the same thing. It pulls from several mythologies to discuss the ultimate battle of good and evil. Plant obviously considers Tolkien's story on par with other mythologies that explain good and evil.