The guideline for foreign language answers still has an ambiguity that has been around since I played:
Can common-noun (eg: "nucleus", "mural", "baptism") answers be given in any language, provided there is no unsportsmanlike attempt to delay the game?
Right now, language rules only specify that geographic places or created works must be answered in English or the native/original language. There is no clarification about other answerlines.
The primary reason for resolving this ambiguity is the use of French in Canada. It is not unusual for a student to have most or all of their education in French, despite being a native English speaker. To a lesser extent, this would affect foreign exchange students who may have had most of their education in another language.
Up to now, I have just recommended to francophone players that they alert a moderator before a match that they might answer non-geographic/created things in French. Since it would be unreasonable to list hundreds of alternate language answers, correctness would be resolved either by a moderator's familiarity with the language or the protest system. No one in a gameplay situation has taken issue with this, but it isn't covered by a rule or guideline.
The other option is to just expand the English correctness to all answers.