If it were an initialization, it would start something. 
The alt.usage.english FAQ calls this an “initialism” and my desktop dictionary agrees. However, I suspect that if you asked a random sample of writers, English majors, or English teachers, “What is an initialism?” you’d get nothing but blank stares.
So this opens up another passionate debate: is FAQ an acronym or an initialism?
barbitu8- clarify what you mean, because according to my reading of this definition:
from dictionary.com seems to conform with “RPG” as being an acronym. And I couldn’t find a definition of “initialization” that corresponds to the concept you expressed. I’m confused…help.
Lemur866: No, RPG isn’t synonymous with role-playing game. That’s the problem. As someone pointed out, RPG is also the name of a programming language. I dare say that if we dug around some more we’d find some other meanings for RPG as well.
So why not use the full “role-playing game” instead of the ambigous “RPG?” The acroynm (uh, initialism) “RPG” doesn’t save any time in conversation, and it saves precious little space on the page. Further, “role-playing game” flows more easily off the tongue than the harsh “RPG.” Using “RPG” instead of the real words is just using an acronym for is own sake, something role-playing games suffer from deeply. (Just look at anything Gary Gygax has ever touched.)
Mind you, I’m talking about formal writing, not ordinary conversation or casual correspondence. Fans and experts will always make up their own incomprehensible private jargon, even if there are better words available.
However, someone who is writing for a broad audience should do their best to resist the siren call of jargon. For example, an economist or a labor leader would find nothing amusing or perplexing in the sentence, “The union demanded COLAs be part of any new contract.” The ordinary reader, however, would probably find the sentence, “The union demanded Cost of Living Adjustments be part of any new contract” far more enlightening.
Just for grins and giggles, some other meanings of “RPG”:
RPG Rocket-Propelled Grenade
RPG Radar Product Generator
RPG Rapid Isotope Power Generator
RPG Rebounds Per Game (basketball statistic)
RPG Reflection Phase Grating
RPG REFORGER Planning Group
RPG Remote Product Generator
RPG Repeating Plasma Gun (Star Wars)
RPG Report Program Generator
RPG Research Planning Group/Guide
RPG Resistance Protein Gene
RPG Reuse Planning Group
RPG Risk Purchasing Group
RPG Rounds Per Gun (aircraft)
RPG Running Power Generation (Mode)
My Bible says: “Use the article an before vowel sounds: an energy crisis, an honorable man (the h is silent), an NBA record (sounds like it begins with the letter e), an 1890s celebration.”
My Bible being the AP Stylebook.
And one would expect the definition of “RPG” to be clear by its context. Nobody’s going to be thinking “Rapid Isotope Power Generator” when they’re reading Inquest. (Though I concede they might be thinking “Repeating Plasma Gun.”)
Note that it’s vowel sounds, not spelling, and “y” doesn’t count as a vowel sound in this context. Hence it’s “an emotion” but “a euphemism.”
No wonder non-native speakers find English spelling so brutal.
Back on acronyms: I was just flipping through channels and lit upon the opening of INDEPENDENCE DAY. A general was talking about receiving a message from a “ess ee tee eye base.” It took some mental effort before I realized he was talking about SETI!
. . . As barbitu8 has alreday stated. An acronym is an abbreviation of a phrase formed from initials or parts of wards which spells out a pronounceable word in itself. Examples include radar and laser. RPG is not an acronym.
I must admit I wasn’t familiar with the term initialism, but here’s the definition from Dictionary.com:
(Emphasis mine.) By this definition, RPG is an initialism, and usage would be “an RPG.” FAQ can be either, depending on pronunciation; as “fak” it’s an acronym, but as “eff-ay-queue” it’s an initialism. My experience has been that FAQ is “fak,” therefore “a FAQ.”
" . . . parts of wards?" What the hell do hospitals have to do with it? Words, dammit, words.
And in case anyone is wondering, here’s the Dictionary.com definition of acronym:
(Emphasis mine.)
Of course, this is absolute nonsense, and I think you know it is. You’re entitled to your contrary views here, of course, but I would think you would garner a little more respect for them by avoiding tortured logic such as this.
Uh, maybe to avoid repeating a rather lengthy phrase numerous times in the course of just a few sentences? Careful writers alternate or at least mix acronyms (or initialisms, if your prefer) and the words/phrases they stand for so as to avoid this.
There’s nothing weak about this recommendation. Like all rules regarding English usage, it reflects current usage, and is sensibly applied to current usage. What does what may or may not happen in the future have to do with anything?
Sure, perhaps one day we’ll suddently revert to writing “to-day,” as was done at the turn of the century. But unless and until we do, such a spelling would stick out like a sore thumb, as does “an historic” and most certainly “a RPG.” (I notice you didn’t acknowledge my comment that 99% of readers would stumble over “a RPG.” This is as compelling a reason as any why it should not be used.)
The Harper Dictionary is American, no? 
To add to the list of “an after H” words: heraldic. As in “An Heraldic Alphabet”, J.P. Brooke-Little.
English person chiming in on cue… apart from a few exceptions (listed by BigStar303), most words beginning with “h” are pronounced with a definite “h” sound, and most of us would say “a” rather than “an”.
Things like “an historic” and “an heraldic” are, I think, restricted to a certain subgroup of (largely upper-class) English speakers. Winston Churchill was one of them, so was Brooke-Little. But I think “a historic” and “a heraldic” would be more common English usage.
(Yes, I’m hopelessly common, myself. I come from a long line of intermittently employed Liverpool dock workers. And I say “a heraldic”, myself.)
You can’t be that common if you’re pronouncing your aitches, Steve 
Heraldry doesn’t feature much in my life, but I tend to say “an historic” whether I’m talking posh or common. In the posh version, historic would be very weakly aspirated, with the stress on the second syllable. That not to say that I don’t occaisionally use “a historic” though, but the stress would be on the first syllable. My accent varies a fair bit.
Thank 'ee, koind marster! (tugs forelock, wrings cap)
But isn’t the stress normally on the second syllable of “historic” (but on the first of “history”) whether you pronounce the “h” or not…?
(So i’m sitting here in an open-plan office muttering “historic… 'istoric… history… 'istory…” People are starting to give me funny looks.)
I, almost without reservation, would say “an 'istoric” and would surely write it that way. But I’m an American, and American from the midwest no less, without any of that New England crap creeping in (until late, of course, where I pronounced coffee exactly like a Bostonian would–good god, what’s happeneing to me!?!).
I tend to find that the word “heraldic” doesn’t come up often in common conversation… well, unless you’re an SCA Herald, or a member of an Heraldic Society.
I use “an” for both Historic and Heraldic. I’m not sure what is most common in New Zealand (I’m a Kiwi, Kiwi parents… albeit that my mother went to what passed for a posh school).
A quick check of the other nit-picking analysts and tech-writers I work with showed a preference for “an historic”… oddly enough they don’t seem to use “heraldic” much.
Hey, here’s a crappy fact that you’ll never use.
The whole H sound thing originated from Greek, but H wasn’t even a letter. Any word that begins with a vowel in ancient Greek has either a rough [kind of like a ( placed over the letter, but smaller] or smooth [the other one, )] breathing mark. The letter H was actually the capital eta (the long A sound in English).
What’s the point? The H originally was not a letter but more of an afterthought. So if it were the same way in English, not only would we say “an historic” but we would write it something like “an ^istoric.” (with some symbol at the beginning).
Now, having said all that, screw history. If it doesn’t sound right, it doesn’t sound right. If you fully pronounce your H’s, use A. If you don’t, use AN.
Nobody is arguing that one should use barbaric acronyms and jargon. Eschew jargon! However, if one does use an acronym/initialism, then one should write the article as one imagines it would be said if the article is read aloud. The only time one would write “a RPG” is if one is certain that every time the phrase is read, it is read “a role playing game”. And that is manifestly not the case…most people would read it as “a arr-pee-jee”, which is wrong.
But yes, I agree with the advise to avoid the term RPG, especially in speach, since it only saves one syllable!!
It’s not only the Brits who don’t always pronounce initial H’s. Many people from the Northeast US, especially from Boston, don’t. I had a former boss who would say “Houston” without the initial H sound - “yooston.”
Also, I believe that there is at least one word that us Merkins pronounce without the H, but Brits say it: “herb.” We say “an 'erb,”, the Brits say “a herb.”
Wumpus, it seems like you’re arguing not about “a” vs. “an,” but whether the initialism “RPG” should be used. You say it only saves one syllable in speech, and is ambiguous in writing. However, in writing, it would not be ambiguous if you’ve already defined it. And since it’s abbreviated in writing, it gets abbreviated in speech. Face it.
No, I really did start out talking about “a” vs. “an.” But we drifted off topic somehow, and this became the Thread That Will Not Die. Still, I maintain that many acronyms (er, intitialisms) are ugly, confusing, and best avoided.
TTFN. K?
An Wumpus