articles - Do you use "a" or "an" before acronyms / initialisms?

99% of the time, I'm clear on when I should use "a" versus "an." There's one case, though, where people & references I respect disagree.

Which of the following would you precede with "a" or "an," and why?

• FAQ


• FUBAR


• SCUBA

[Note: I've read the questions "A historic..." or "An historic…"? and Use of "a" versus "an", but the rules given there don't necessarily apply here.]

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[Edited to add]

Here's a shorter (and hopefully clearer) version of the question… In written English, which is correct (and why): "a FAQ" or "an FAQ"?

Some references with differing opinions:

Answer

It depends on whether the abbreviation is an acronym or an initialism. As "fubar" and "scuba" are usually pronounced as a word (making them acronyms), it would make sense to say "a fubar" and "a scuba diver". "FAQ" is a bit harder, because I have heard people say it like an initialism: "‹f›‹a›‹q›", while others pronounce it as an acronym /fæk/. Therefore, one should write either "a FAQ" or "an FAQ" depending on how that person pronounces it, ie, whether it is an acronym or an initialism.