Demented and Mary, apologies about the homophones comment. I thought I'd covered myself with the 'some English dialects' caveat, meaning dialects spoken in England, as opposed to dialects in Scotland (or anywhere else in the English speaking world, come to think of it). I am sorry if my comment offended. I'm not even English, but do teach phonics in England. My familiarity with Scottish dialects is limited and I'd be really interested in examples where -ir / -er / -ur are not homophones.