"a" or "an" in front of an acronym?

[Shahar26]

What's the rule here?

I've seen a WTA player and an ATP player, but also an SLR camera :?

[Flyingpanda]

The a or an is determined by the sound of the first letter, not the spelling. This goes for acronyms and words. In your example a WTA player. The first sound is the "duh" in W. In the acronym SLR, the first sound is the "es" in S.

[Shahar26]

The a or an is determined by the sound of the first letter, not the spelling. This goes for acronyms and words. In your example a WTA player. The first sound is the "duh" in W. In the acronym SLR, the first sound is the "es" in S.

Thanks! 10 chars