Postillions I have known...
. . . can be counted on none finger.
Richard Nokes of Unlocked Wordhoard has unlocked a teeming horde of seductive words with his Ideology of Phrasebooks and thereby prompted my memory of an unforgettable phrase:
"Our postillion has been struck by lightning!"
I believe that I first read this sentence in an essay used by Sheridan Baker, perhaps in his Complete Stylist, which I have in my office and thus cannot immediately check, or possibly in his Practical Stylist, though I don't find it in either the sixth or eighth edition.
The sentence was given as an example of useless phrases in guidebooks -- useless because vanishingly unlikely to be needed in any reasonable circumstances. But the essay's author went on to note the more interesting point that most dialogue provided by guidebooks is useless because, outside of a few very simple requests, most of the sentences offered are unlikely to be needed.
Even the simple requests sometimes misfire:
Hapless tourist: "Where is the toilet?"
Native Speaker: "In the bathroom, you idiot!"
This is an entirely plausible dialogue, but most guidebook dialogues are implausible.
In fact, most of the remarks that we utter each day are novel constructions. The essay's author noted this point and used it to introduce Noam Chomsky's linguistic theory of generative grammar, which argues that 'deep' grammatical structures generate an endless variety of 'surface' sentences.
Using Google, we can test the essayist's point that most sentences are novel. Go to Google's Advanced Search webpage, find the slot labeled "with the exact phrase," and type in the simple sentence "I'd like to buy Gravity's Rainbow."
Nothing comes up.
Try it with simple and with complex sentences of your own making. The more complex the sentence, the less likely it is to show up, but even quite simple sentences are often novel and fail to show up in an advanced google search.
This doesn't prove Chomsky's theory, but it does illustrate the flaw behind most guidebooks that provide 'handy' phrases for the language-deficient traveler.
But you're still wondering about postillions. Let's check Webster for its definition of "postillion":
one who rides as a guide on the near horse of one of the pairs attached to a coach or post chaise especially without a coachman
This doesn't clarify much, but it does suggest the statement's implausibility. The unlikelihood of anyone ever needing to say anything about a postillion has raised doubts that the statement or a variant of it ever appeared in any guidebook's handy phrases. Those doubts can now be allayed if not quite extinguished, for one intrepid soul, Nigel Rees, has found some tantilizing evidence:
Q729 An actual source for the famous phrasebook line, 'My postillion has been struck by lightning'. In Karl Baedeker's The Traveller's Manual of Conversation in Four Languages (1836 ed.) is: 'Postilion, stop; we wish to get down; a spoke of one of the wheels is broken.' In an 1886 edition I have found: 'Are the postilions insolent?; the lightning has struck; the coachman is drunk.' From these examples it is quite clear that the preposterous phrase could quite likely have appeared in Baedeker or similar, but where? In 1935, the phrase was said to come from a Dutch phrasebook.
These examples get us pretty close, but as my high school coach used to say, "Close only counts in horseshoes and hand grenades."