[Formendacil]

While considering the goblin song, I think it's worth remembering that the literary genre of The Hobbit is (at least ostensibly) a tale for children. Rather than looking at the goblin-song with an eye towards reconciling it completely with what is said about orks in The Lord of the Rings and subsequent works, it seems to me that this might be a good point to remember the author and audience instead.

After all, The Hobbit has a distinct narrator--certainly more so than The Lord of the Rings--and the Conceit is that we're reading a retold version of Bilbo's memoirs. Even "within the story" then, it might be fair to suggest that the goblin song, as we have it, isn't an entirely accurate representation of what the goblins were actually singing (or chanting... or screeching... or screaming... or whatnot). It could just as easily be conceived as Bilbo whimsically taking the rather unpleasant experience and using it as interpretation to write one of his trademark poems. Certainly, the author of "the Cat Jumped over the Moon" seems a better author for this poem than the orks of the Misty Mountains--however clever the they (and the lyrics) are.

Ignoring the Translator Conceit entirely, it seems to me that the poem is Tolkien's way of keeping the danger and fear of the scene to a level a younger child could handle. As far as that goes, it's quite clever, because it uses the threat that the goblins pose as its subject, but its form makes it more of a laughing matter for the audience than one of dread. In other words, Tolkien is able to deepen our sense of danger while simultaneously easing the possible nightmares--and, at the same time, indulging his own creative whimsy.