Is it correct to use indefinite articles based on the spelling of a word or the way it's pronounced?
Would we say "Take an NHS leaflet." or "Take a NHS leaflet."?
Also, what is the case with words which are pronounced differently in different parts of the world?
For example would it be "an historian" in the UK, while "a historian" in the US? Which of the two historian versions would be selected for a book that would be sold internationally?