A friend asked me how to determine whether to use “a” or “an” with acronyms, and I realized that the problem also includes whether “a” makes the long “ay” sound or the “uh” sound and whether “the” is pronounced “thee” or “thuh.” So here’s a quick cheat sheet.
Use the indefinite article “a” before words or acronyms in which the first sound is a consonant, a voiced “h” (a history lesson) or along “u” sound (a usual practice). Various publishers have decreed that SQL is pronounced “see-kwell” when the application SQL Server is being discussed (“a SQL Server database”), but check with your publisher before assuming. Most of the time with “a,” you can use either the long or short vowel sound no matter what the word is that follows, although the “uh” version often sounds less awkward, especially when the preceding word ends with a consonant or a hard “y” sound (like: "modify a noun").
Use the indefinite article “an” before words that start with a vowel, except those with the long “u” sound, and before words beginning with an unvoiced “h” (an honest opinion). That means that mention of the SQL language (“ess-kyoo-ell”) takes “an,” as does the acronym ASCII.
The definite article “the” is pronounced “thee” when it precedes a vowel or unvoiced “h” (the apple and the honor). “The” is pronounced “thuh” when it precedes a consonant or a voiced “h” (the bell and the habit). The long “u” sounds like it actually begins with a “y,” so you can treat it is if it were a consonant and pronounce it “thuh.”
You don’t have to repeat the indefinite article when you’re referring to two or more separate nouns (a plum and banana), unless you are referring to roles played by people (a painter and a poet) if there is more than one person involved. When talking about people, not repeating the article says that all the people in the sentence are one and the same, as in “an officer, pilot, and doctor.” If you put an article before each noun, there are three people (an officer, a pilot, and a doctor). You have to include an article for every noun if there is more than one beginning sound and you need more than one type of article, “a plum, a banana, and an apple.”
It has become commonplace to leave articles off, especially in advertising copy. I can’t think of a logical reason to do that, unless space is a serious issue. Which of these sentences is clearer?
A bad penny brought the bad luck
Bad penny brought bad luck.
Only the first one is completely clear. The second sentence is pigeon English. I won’t ding you for speaking that way, but please don’t write that way.
Oh, and one more thing: it’s “on the average,” not “on average,” for the same “needs an article” reason as the “bad penny” sentence.