An eye doctor invented a language to end war between nations

In 1887, Polish-Jewish ophthalmologist L. L. Zamenhof published a new constructed language he hoped could serve as a neutral second tongue for all of humanity, reducing the misunderstandings he blamed for conflict in his multilingual hometown. He called it "Esperanto," one who hopes. It remains the most widely spoken constructed language ever created.

— L. L. Zamenhof, Unua Libro (International Language) — 1887