With the OED in electronic form it should be possible to give a fairly
close number for the total number of words in English. Back in the '50s
I remember Albert Marquardt saying the estimate of the English
vocabulary was arrived at by counting the number on some number of
pages, getting an avarage, & multiplying by the total number of pages.
In other words, no one really knew how many words there were in the
English lexicon or even how to define what "A Word" was.