In order to be listed, a language must be classified as "endangered" in a cited academic source.

Researchers have concluded that in less than one hundred years, almost half of the languages known today will be lost forever.

[2][3] When judging whether or not a language is endangered, the number of speakers is less important than their age distribution.

There are languages in Indonesia reported with as many as two million native speakers alive now, but all of advancing age, with little or no transmission to the young.

Experts predict that even in a conservative scenario, about half of today's languages will become extinct within the next 50 to 100 years.