Some of it may be due to the ancestor's local accent. I have a female ancestor who was baptised 'Susaner' (yes, it's actually written that way in the baptism register!). I also have a family named Heawood in one census - because that's how 'Haywood' would have sounded in a strong West Country accent. My own grandfather, when he registered the birth of my mother, was put down as 'William Rupert Ball', when he should have been 'William Hubert Ball'. But I was a small girl when he was still alive, so I can remember just how thick his accent was - and I can well believe it!