If we're going to have 'official' names for major geographic features (which would certainly be convenient) then I'd prefer to keep those as generic, meaningful english terms. "Northeastern temperate continent", "southern subarctic island" and so on. Or even use some kind of numbering system, eg. C1, C2, C3... for continents; R1, R2, R3... for major rivers; A1, A2, A3... for archipelagoes; M1, M2, M3... for mountain ranges.

Obviously these official names would not actually be used by the inhabitants of the setting. They're merely for us to have a common reference set. Next to each official name there could be listed any number of proper place names that represent what those places are called by the various cultures and languages of the setting.