Noah Tesch was Associate Editor for Encyclopædia Britannica. How would it feel to be the last person on Earth who speaks your language? For those of us whose native languages have millions of speakers, it’s almost impossible to imagine. And yet languages have come and gone throughout human history, and they continue to do so. Linguists estimate that of the world’s approximately 6,900 languages, more than half are at risk of dying out by the end of the 21st century. Sometimes languages die out quickly. This can happen when small communities of speakers are wiped out by disasters or war. In El Salvador, for example, speakers of the indigenous Lenca and Cacaopera abandoned their languages to avoid being identified as Indians after a massacre in 1932 in which Salvadoran troops killed tens of thousands of mostly indigenous peasants in order to suppress an uprising.