Glottochronology is the methodology used by linguists to determine how many years have passed since two modern languages “branched” from a common ancestor. Experiments suggest that if N words are in common use at a base time t = 0, then the number N(t) of them still in use with essentially the same meaning t thousand years later is given by the so-called fundamental glottochronology equation* N(t) = N₀e^−0.217t

a. Out of a set of 500 basic words used in classical Latin in 200 B.C., how many would you expect to be still in use in modern Italian in the year 2010?

b. The research of C. W. Feng and M. Swadesh indicated that out of a set of 210 words commonly used in classical Chinese in 950 A.D., 167 were still in use in modern Mandarin in 1950. Is this the same number that the fundamental glottochronology equation would predict? How do you account for the difference?