For example “I have an MBA” and “I know a mechanic”. When you pronounce the M from MBA, you hear the e in front, you’re saying em-bi-a. But for mechanic, you j

For example “I have an MBA” and “I know a mechanic”. When you pronounce the M from MBA, you hear the e in front, you’re saying em-bi-a. But for mechanic, you just have a stromg m. This is what I mean by “if it sounds like a vowel”. And hence an and a.