Well, the idea is to make the SpellChecker as simple to use as possible, not requiring users to also download and include their own spell checker library. As you noticed, if you want to use a different spell checker library you can easily write your own, copying how SpellChecker interfaces with RSTA. I’m trying to keep the API to do so simple (just implementing Parser) just for that reason.

Of course, I’m open to suggestions for this add-on (since it’s still in its infancy). A way to better abstract the engine from the SpellChecker add-on (while keeping it simple to use), or even just a better engine (though I prefer it to be LGPL, BSD or something similar to keep the add-on as usable as possible), or anything else.

A minor quibble (I was able to work around the problem very easily by replacing SpellingParser with my own version): I don’t like the way Jazzy is currently integrated in a largely hardcoded and monolithic way. It would IMHO be a lot nicer to have a simple interface to connect any 3rd party spellchecker.