Isaiah 14:4 (Latin Vulgate): sumes parabolam istam contra regem Babylonis et dices quomodo cessavit exactor quievit tributum
Knox Translation: "it will be thy turn to have thy say against the king of Babylon. Can it be (thou wilt say) that the tyranny is over, the exactions at an end?"
I don't think there is any doubt that Isa. 14:4 (LXX) can be rendered with the use of "parable" although I will admit there are other ways parabolam may be handled or understood in the passage. But the Douay-Rheims treats the verse as follows: Thou shalt take up this parable against the king of Babylon, and shalt say: How is the oppressor come to nothing, the tribute hath ceased?
See the definitions given for parabola at http://www.perseus.tufts.edu/hopper/text?doc=Perseus:text:1999.04.0059:entry=parabola
In any event, the literary context causes me to believe the words found in Isa. 14:12-20 are symbolic, poetic--not to be taken literally.
The language "Yet thou shalt be brought down to Sheol, to the uttermost parts of the pit" (ASV) are echoed elsewhere in the Tanakh and appear to be clearly tropical (i.e., non-literal). Compare Ezek. 31:1-2,15-17.