Should one use "an" or an "a" before an acronym beginning with the letter H?

Question

Consider the sentence:

He offered to be an HSC.

vs:

He offered to be a HSC.

In the example above, HSC stands for Health Service Consultant. If one were saying the sentence aloud, one would say an HSC because an obviously proceeds the spoken letter H, but the H actually represents the word Health, at which point the sentence should perhaps read a HSC because one would obviously say a Health Service Consultant. If one considers what the letter H actually stands for, in a strange way, both versions could perhaps appear to be incorrect depending on whether the acronym is viewed by the reader solely as a contraction or as its real meaning.

I would surmise that an HSC would be the more correct grammar, but I'd like opinion.

Answer 1

As several people have already stated, in both speech and writing, the only thing that matters is how the particular writer/speaker would pronounce the sound that follows the indefinite article. If he or she would pronounce that sound as a vowel, it should be 'an', and if as a consonant, it should be 'a'.

Now we apply that rule to your case. In American English as well as in standard UK English, the 'H' in HSC is pronounced 'aitch'. Let's assume that this is how you would pronounce it, too. 'Aitch' begins with a vowel sound, and so should be preceded by 'an'. Thus, you should write it as

He offered to be an HSC.

However, as Ian MacDonald and tmgr have pointed out (and which this article confirms), in the UK, people increasingly pronounce 'H' as 'haitch'. If you are one of these speakers, then you should write it as

He offered to be a HSC.

Here is how this is explained in the Chicago Manual of Style:

(begin quote)
7.33: “A” and “an” before abbreviations, symbols, and numerals

Before an abbreviation, a symbol, or a numeral, the use of a or an depends on (or, conversely, determines) how the term is pronounced. In the first example below, “MS” would be pronounced em ess; in the second, it would be pronounced manuscript. In the last two examples, “007” would be pronounced oh oh seven and double oh seven, respectively.

an MS treatment (a treatment for multiple sclerosis)
a MS in the National Library
an NBC anchor
a CBS anchor
a URL
an @ sign
an 800 number
an 007 field (in a library catalog)
a 007-style agent

10.9: “A,” “an,” or “the” preceding an abbreviation

When an abbreviation follows an indefinite article, the choice of a or an is determined by the way the abbreviation would be read aloud. Acronyms are read as words and are rarely preceded by a, an, or the (“member nations of NATO”), except when used adjectivally (“a NATO initiative”; “the NATO meeting”). See 10.2; see also 7.33.

an HMO
a UFO
a NATO member
a LOOM parade
an AA meeting
a AA battery (pronounced double A)
an NAACP convention
an NBA coach
an HIV test
an MS symptom (a symptom of multiple sclerosis)

but

a MS by... (would be read as a manuscript by...)

Initialisms, which are read as a series of letters, are often preceded by a definite article (“member nations of the EU”). Whether to include the article may depend on established usage. For example, one would refer to the NBA and the NAACP, on the one hand, but to W3C, PBS, and NATO, on the other—though all these organizations include the definite article in spelled-out form. If no established usage can be determined, use the definite article if it would be used with the spelled-out form. Some terms, such as DIY (do it yourself), do not ordinarily require a definite article in spelled-out form and therefore do not require one as an initialism.
(end quote)

Answer 2

Pronunciation of the following sound is the only thing that dictates the use of a vs. an: vowel sounds get "an," consonants get "a." In particular, in the case of initialisms, what matters is how the letter is pronounced, not whether the letter represents a vowel or consonant sound. The letter "h" (usually) represents a consonant sound (though it is often silent - whether you say "a herb" or "an herb" depends on whether you pronounce the "h" in your dialect), but when we say "h" we're really saying something along the lines of "aitch," which begins with a vowel sound (EDIT: see comments, this appears to not always be the case, but in either case you'd use whatever's appropriate for the sound).

Therefore, you'd say "an HSC."

Answer 3

Here is an Ngram chart tracking the frequency of occurrence in the Google Books database across the period 1955–2008 of "a HHS" (blue line) versus "an HHS" (red line) versus "a HUAC" (green line) versus "an HUAC" (no line because there are too few instances to plot):

As you can see, "an HHS" and "a HUAC" dominate their alternatives. This reflects the fact that people normally pronounce "HHS" (short for "[Department of] Health and Human Services") as an initialism ("aitch-aitch-ess"), but they normally pronounce "HUAC" (short for "House Un-American Activities Committee") as an acronym ("hew-wack"). The choice of indefinite article then follows from the pronunciation of the first syllable of the pronounced wording ("an aitch-" and "a hew-").

I imagine that this preference extends pretty generally in English across all initialisms and acronyms that begin with "H."

Answer 4

Other answers are correct in stating that:

Pronunciation of the following sound is the only thing that dictates the use of a vs. an: vowel sounds get "an," consonants get "a."

The reason this is a thorny issue, however, is because initial "h"'s are pronounced in most dialects of formal American English, but there is an influential upper class white minority dialect of American English in the Northeast United States (and especially among upper class residents of the Boston, Philadelphia and New York City areas which are home to the very intellectually influential Harvard University, and other leading U.S. private universities, whose pronouncements are often taken as definitive) and in the vicinity of Cork, Ireland, which makes the initial "h" in many words such as "human", "huge" and "Harvard" silent.

This is called H-dropping. Historically, H-dropping was a deliberate effort dating to the Colonial period to differentiate American English from British English by having high status people adopt what in England is a low status dialect feature: "Although common in most regions of England and in some other English-speaking countries, H-dropping is often stigmatized and perceived as a sign of careless or uneducated speech."

So, the indefinite article in 95% of the U.S. may differ from the correct indefinite article in the dialect of American English most common at Harvard University which is often viewed by status conscious people as definitive.

Thus, your choice of indefinite article necessarily reflects an editorial and stylistic judgment regarding which of two high prestige dialects of American English is correct.

For example, most Americans would say "a Harvard graduate" but many graduates of Harvard University would say "An Harvard graduate", due to a silent "h" in Harvard in that dialect.

(Growing up, one of my frustrations with grammar instructions as a child was similar. Our textbooks all stated that "our" and "hour" were "homophones", even though they had very different pronunciations in my dialect of American English, in which the one syllable word "our" was instead a homophone of the one syllable word "are", and "hour" was a two syllable word.)