The noble knight brandishes his sword in the air. "Come out, vile worm!" he calls. There is a scraping of scales, and out comes a large dragon. He has an annoyed expression, with perhaps a hint of boredom.
"Oh, all right, let's get this over with," he grumbles, "but really, can't you learn a little better English?
"Pardon?" says the knight, a little put out. He wasn't really expecting a lesson in his own language.
"Well," says the dragon, "you called me a worm. Surely you can tell the difference between an earthworm"-here he holds up an example-"and a magnificent dragon such as myself."
"Errr." The knight does not really know what to say to this; he watches as the dragon regards him, coolly, as if wondering whether or not he will say something intelligent. "Well, it's a proper name for a dragon, like a term of sorts, isn't it?" he ventures.
"No. Actually the correct term would be wyrm, W-Y-R-M, pronounced 'wirm', not 'wurm'."
"Oh." The knight thinks about this.
"Well," says he at last, "it doesn't really matter, does it?"
"No," says the great firedrake firmly, "it doesn't."
And with a loud SNAP-CRUNCH, the knight is gone. The dragon pads back into his cave in a rather bored fashion and settles down for a long rest, thinking absently of a good book and a cup of tea.