Hi Kris,
Thanks for this very encouraging response. Your proposed implementation sounds like the best one: the app shouldn't fiddle with the selection, it should just intelligently parse the word when being looked up in the dictionary. Hard-coding the prefixes is also a great choice because it will prevent errors when looking up the occasional word that has an apostrophe in it, like
aujourd'hui.
I'll send you a complete list of prefixes once I've done some testing on the built-in dictionary. Oddly, iOS 8 seems to have
broken my default dictionaries and I can't look up any words or download/delete dictionaries anymore.