Aspell is a command line, interactive spell checker. I plan to build a script which saves my misspelled words and their corrections to a file so that I can practice their correct spelling later. I could build and spaced repetition system to improve my spelling, which would target only those words with which I've struggled. This would require disabling active spell checking, but that might improve my focus. I would need a system to differentiate typos, which I do not believe require practice.