“[I]t might be that some ancient languages had altered very little and had given rise to few new languages, whilst others had altered much owing to the spreading, isolation, and state of civilization of the several co-descended [people groups] and had thus given rise to many new dialects and languages. … In confirmation of this view, let us glance at the classification of varieties, which are known or believed to be descended from a single species. These are grouped under the species, with the sub-varieties under the varieties… with several other grades of difference.”

— Charles Darwin