If you are doing a production grade spellchecker (or for that matter, anything ML) I would suggest that you spend some time getting familiar with the literature

If you are doing a production grade spellchecker (or for that matter, anything ML) I would suggest that you spend some time getting familiar with the literature survey (Google Scholar is your friend). I have done various implementations over time (and also, as it happens, specifically a spellchecker, but that was not meant to be production grade), and I find this to be the most rewarding way in the long run.