If a word begins with a consonant sound, use the indefinite article a.
If a word begins with a vowel sound, use the indefinite article an.
This article satisfies Squid Commo Objectives #2: Suffer not bullyery and #3: Clarify and simplify the rules.
I'd like you to try something.
Starting with A, run through the alphabet and identify each letter by saying, "It's an A," "It's a B, "It's a C," and so forth. What happens when you get to F, H, L, M, N, R, S, and X? Despite the fact that these are consonants, you used the indefinite article an, which is normally reserved for vowels. A quick moment of reflection reveals that you used an because saying those letters out loud makes them, in effect, words that begin with a vowel sound. "An F," "an H," and so forth.
So that's my recommendation for choosing your indefinite article. Use that natural instinct. If a word begins with a consonant sound, use a as the indefinite article. If it's a vowel sound, use an.
This way of doing business bypasses all that nonsense about words that begin with H requiring an as their indefinite article, e.g., hypothesis, horrendous, horrific , hallucination, hysterical, and historic.
That piece of pretention is supposed to be applied to H words that are accented on the second syllable. That by itself is uncomfortably and unnecessarily snooty for 99.99% of the English-speaking world. But then, there are those pesky exceptions that cast doubt on the soundness of the rule, because even the 0.01% would never say, "Let's stop at an hotel" or "Give the governor an harrumph!" So we end up constructing exception-laden rules that take as long to memorize as the periodic table of elements.
So let us reject the snoot and instead revel happily ever after in the perfect simplicity of a world where everyone exceptionlessly and compassionately* invokes a when the word begins with a consonant sound and an for those that begin with vowel sounds.
It's a historic occasion.
It's an honor to be with you on this historic occasion.
__________
* It's compassionate, because it allows those who pronounce certain H words without the H (e.g., Cockney and Latinate) to use an without lousing up the lotusland.In speech, pronouncing the definite article, the, follows this same idea.
For words that begin with vowel sounds, you say, "thee."
"thee" eagle
"thee" apple
"thee" Honorable
For words that begin with consonant sounds, you say, "thuh."
"thuh" hawk
"thuh" banana
"thuh" Right Honorable
Of course, emphasizing a and the is something altogether different.
This is "thee" hip, cool, happening dojo for business students.
No, this is just "ay" dojo, not "thee" dojo for business students.