A vs. An

I was taught growing up that you use “a” when the word starts with a consonant, and you use “an” when the word starts with a vowel. This is close to being right, but not really.

I heard a few years ago that you’re also supposed to use “an” for any word starting with the letter “h,” but that’s even more wrong! I was originally confused because I had realized that "an honor" sounds correct, but "an hairy ape" does not, and I'd keep hearing or seeing things like "an heroic..." but I think it was then that I realized not a whole lot of people know when to use "a" and when to use "an."

After I did some research, I’m pretty sure I bonked myself in the head and said, “duh!” It seems rather obvious, but I guess it wasn’t for me. The actual rule is that you use “a” when the next word starts with a consonant sound and you use “an” when the next word starts with a vowel sound. It doesn’t matter what actual letter the word starts with - just the sound matters. So there you go.

But of course, this is the English language, and what would the English language be if it didn’t try to confuse you?

Some words can sound like they start with a vowel sound or a consonant sound, depending on a few things. For example, when I say “a historic event,” I pronounce that “h” because it sounds right and the statement sounds grammatically correct. But if I say “an historic event,” it also sounds right, because I say “historic” really as “istoric” without the “h.” The real test on whether to use “a” or “an” on words like that is to say the word by itself, then use “a” or “an” appropriately for that pronunciation. So the right way to say it would be “a historic event," unless of course you’re one of the few people who always pronounce it as “istoric,” then go ahead and say “an.”

Quick version: use "a" to precede words that start with a consonant sound, use "an" to precede words that start with a vowel sound.

References:
Online Writing Lab
Grammar Girl

Grammar Girl and OWL are my two main go-to websites for anything related to the English language. I have a decent history with the a vs. an situation, and I’m embarrassed to say that it has taken me this long to actually figure it out, lol.