A vs. an is based on pronunciation

I always thought “a” vs. “an” was based on the written first letter: use “an” before words starting with vowels - a, e, i, o, u.

But some words felt weird when I wrote them, and I never noticed which article I was using when speaking.

Turns out the actual rule is based on pronunciation, not spelling:

• “an hour” because hour sounds like “our”
• “a university” because it starts with a “yoo” sound
• “an MBA” because M is pronounced “em”
• “a European” because it starts with a “yuh” sound
• “an honest mistake” because the H is silent

The more you know.