I'm British and I have never personally pronounced it "istoric", and to my knowledge I have never heard anyone pronounce it like that either. Is it a regional t

I'm British and I have never personally pronounced it "istoric", and to my knowledge I have never heard anyone pronounce it like that either. Is it a regional thing? I can only recall it being pronounced like that in US TV shows with comedy fake English accents. "An hour" on the other hand makes more sense, as that is truly a soft H.