As "Joan", "Joanna" or "Jane", presumably. Slightly off-topic: I can't find a link, but I'm sure I read somewhere that Irish speakers in the nineteenth century

As "Joan", "Joanna" or "Jane", presumably. Slightly off-topic: I can't find a link, but I'm sure I read somewhere that Irish speakers in the nineteenth century would routinely anglicise their own names when writing in English: e.g., a man called Sean would sign letters as "John".