-er and -a are virtually identical in most parts of England, too. Those sorts of phonetic spellings happen in England even now, and I'm pretty sure they're not deliberate. Quite recently I saw a girl in the paper listed as 'Natasher'.
I just searched Victorian birth records for England & Wales and found several 'Lear's with female middle names. Also, several Ethers, and a couple of 'Etherline's and 'Etherlinder's, which suggests an etymology.