That’s the title of a paper (pdf) by David Clingingsmith of Case Western Reserve University; the abstract says:
Scholars have long conjectured that the return to knowing a language increases with the number of speakers. Recent work argues that long-run economic and political integration accentuate this advantage, leading larger languages to increase their population share. I show that, to the contrary, language size and growth are uncorrelated for languages with ≥35,000 speakers. I incorporate this finding into an evolutionary model of language population dynamics. The model’s steady-state follows a power law and precisely fits the size distribution of the 1,900 languages with ≥35,000 speakers. Simulations suggest the extinction of 40% of languages with <35,000 speakers within 100 years.
It looks interesting and well written but quickly gets into more statistics than I can handle, but I’m sure some of my readers will have no problem with it. (Incidentally, if you’re curious, as I was, about the name Clingingsmith, there’s a book called Klingensmith, Klingelsmith, Clingingsmith, Etc, which is suggestive if not very enlightening.) Thanks, Kobi!