Did you see this article last week? I thought it was pretty interesting: “Undocumented Language Found Hidden In India.”
Key quote:
Previously undocumented languages are “noticed from time to time” Harrison said, so such a discovery is not rare. But at the same time linguists estimate that a language “dies” about every two weeks with the loss of its last speakers.
Apparently there are 6,910 documented languages in the world, so by my math we still have 265 years before we’re all speaking Chinese.