Actually, for the communication of everything from exacting technical work to fairly abstract ideas, English doesn't do too badly.
In fact, as compared to some others, English is preferred.
Others do fine with poetry, some of the mythological poems in Tamil cannot be done justice in anything else.
For religious works, you've got to learn Amharic, some of the books of the Ethiopian Orthodox Bible have yet to be translated into anything else.
And, of course, you haven't read Gilgamesh until you've read it in the original Akkadian.
But, failing that, I'll stick to American English.