The particularly nasty Wordstone placed in Jon's possession was the Practiced Wordstone.
The bearer of this stone would be transformed to suit the first three adjectives they utter while making a wish, the very second the final wish is granted.
These changes are not wishes in themselves and so may be countered. However the stone itself will resist any attempt to remove these attributes - though, as bound by Fae law, a perfectly worded wish can remove these alterations completely.
Should the victim of the curse no longer resemble the three descriptive elements thrust upon themselves (by any means), they will be free of the curse "“ and free to be cursed again...