Just a thought:
expression (invinitive in case of a verb) - declensed form - description - validity for language
gehen - gegangen - verb, past participle - valid for German, English, French, Italian etc.
whereby in "description" you store the type of declension and in
valid for: all languages where this type of declension exists
then you have a "if espression language is German make available all description forms valid for German" that will show only the possible declension forms for the language being edited.