The phrase-level fallback is a sensible contract: an uncertain token should not leave a half-declined dedication. I would preserve separators as well as casing when reconstructing accepted forms. Joining every token with a space can change a hyphenated name, an apostrophe, or an initial even when each word was inflected correctly.

Token spans can carry the original separators, with only the word spans replaced. A small boundary guard is also worth adding to the illustrative Russian suffix rule: the final-a branch reads w[-2], so a one-character input needs handling before that lookup. These cases belong beside the linguistic trap list because they test input preservation rather than morphology.