As no one seems interested in this too precise question, I can try to generalize: has some consensus been reached about the official language to use for tagging ? (between american and british english, obviously).
I think on the map end of the story, a renderer should be able to handle both. As to which it will prefer if both are present, that’s an open question.
I agree that renderers should do some “best effort” if reasonable, but on the other hand we should choose one unique tagging for each feature, else every attempt to interpret the data would be too complicated.