stai usando plurali dove in italiano non li usi.

-question's languages oppure question languages (puoi omettere 's)
-allo stesso modo, form languages
-user answers report
-closed and open questions significa altro; potresti dire inactive questions report e..
-active questions report
-unable to remove a contact from questionnaire. user has already answered
-languages not compatible (potresti aggiungere "with each other")

cmq il genitivo plurale si fa con l'apostrofo soltanto.
es. Italians' favourite fast-food is sliced pizza.