xmrsmoothx

*Claps for native*

I'm sorry, but you are incorrect. "An RP" is very valid. The choice between "a" and "an" is based entirely on whether the word is pronounced beginning with a consonant sound or a vowel sound, the purpose of the system to be to smooth out speech, reduce the number of complex syllables, etc. For abbreviations, you therefore use "a" or "an" depending on how the abbreviation is pronounced on it's own, regardless of how the unabbreviated word is pron...

An abbreviation should always be pronounced as its composite words.