As any modern student knows, nearly all published research these days is in English. That's just the way of the world. But it didn't used to be that way. Many of the most pivotal pieces of scientific literature in the world, like the writings of Riemann, Cantor, Einstein, Galois, Schrödinger, (Gregor) Mandel, Linnaeus and many, many others were written in German, French or Latin. These days, publishing in a language other than English hurts your credibility, and is largely discouraged.
When did English become necessary for publishing scientific literature?