A common problem for rosetta-stone and polyglot challenges (and some code-challenges) is to decide when two different languages/dialects are different enough to be counted separately. Common borderline cases are C/C++, ECMAScript 5/6, Python 2/3. Very often it's possible to get one of those for free. People try to rule those out by saying things like "you may not count two versions of the same language", which gets the last two cases. But stuff like C/C++ is usually harder to rule out.
I'm asking because I'm considering to change this proposal to score by the number of different languages used.
Can we come up with some standard rules for when two languages are considered different enough for the purposes of these challenges?