[STCrowley]

I don't know. Latin stuck around for a long time as the language of education. . . and it was considered a step 'backward' in education when schools stopped using it. And I know a chemist who had to learn German in university, because it was the language of chemistry. . . these things really are tenacious.

I predict that it won't be Chinese. Just because that seems like the obvious answer. I say Spanish, but mainly to be contrary.