Ironically, though this blog is a grammatical nightmare, I solved a grammatical mystery without referring to the internet: I was reading Alan S. Blinder's book After the Music Stopped: The Financial Crisis, the Response, and the Work Ahead and I noticed that in the phrase "an FDIC insured bank" there is the use of "an" before a consonant -- but a consonant in an abbreviation-- and I wondered why this was so, and then I remembered when Keanu Reeves says to Patrick Swayze "I am an F!B!I! agent" in Point Break and you also say "an X-ray" and "an NBA game" but you say "a WNBA" game and it is because when you say the name of certain consonant letters . . . and you only do this in abbreviations . . . then these consonant letters begin with a vowel sound (so for "F" you say "eff" and for "X" you say "ex" and for "N" you say "en") and so the article matches the sound of the letter, not the designation of the letter, and creates an interesting exception to the rule (or at least I find it interesting, but I'm sure most of you are asleep by now).