Zach Weinersmith, of Saturday Morning Breakfast Cereal, proposed the above hypothesis, and then asked if anyone wanted to try writing a program to convert all non-nouns to "nurble". I gave it a shot, with an exceedingly quick and dirty command-line PHP script which, while imperfect, worked better than expected.
This is a slightly improved version, rewritten for the Web, which now actually handles plural nouns reasonably well (the part-of-speech database, obtained from sourceforge, does not contain very many plurals, so this script checks to see if perhaps an unrecognized word is actually a plural noun). It is still far from perfect, as there are a number of words which are tagged as multiple parts of speech ("hollow", for example, could be an adjective, noun, or verb), and the database sometimes makes rather curious choices regarding parts of speech ("or", for example, is tagged as a noun and an adjective, but not as a conjunction).
Enter the text to be nurbled: