Definition: To linguify a claim about things in the world is to take that claim and construct from it an entirely different claim that makes reference to the words or other linguistic items used to talk about those things, and then use the latter claim in a context where the former would be appropriate.
I note in passing that linguifying a claim is usually (but not always) done in such a way that the new claim is false instead of true, and it is often (but not necessarily) done with the intention of achieving a humorous effect.
Hmmm. To linguify claim 1 about X is to take claim 1 and construct from it a claim 2 about X, then use claim 2 in a context where claim 1 is appropriate.
Here's an example Pullum quotes:
"Movies, theater, parties, travel--those are just a few of the English nouns that parents of young children quickly forget how to pronounce."
Okay, let's find a simpler way of saying this :
"Linguifying" is making a false or exaggerated claim about how people are using language, generally a claim intended to be taken as mild humor.
Wall Street Journal's Best of the Web has linked to a recent Pullum post applying the term to an NPR interview. Pullum is highlighting typical political spin, where Condoleeza Rice observes a juxtaposition of ideas in a question and exaggerates her negative reaction for effect.
So I'll have to expand my simplified definition :
"Linguifying" is making a false or exaggerated claim about how people are using language, often either (1) a claim intended to be taken as mild humor, or (2) a complaint intended to divert attention or close off dialogue on a touchy subject.
I'd also link to Taranto's Best of the Web, but they don't make it available for a day or so after it goes to the email list.