A good book on this is Proto by Laura Spinney, it covers all the branches of Proto-Indo-European and also postulates that the entire family may have started from as few as a hundred speakers who were steppe nomads, which is mindboggling if true.
There was a wealthy Italian who was building a villa in the US, and told the architect he wanted a "hollow statue" in it. The architect looked far and wide for a hollow statue, without success. Finally he came back to the client and told him that no one he talked to had heard of hollow statues. The client said, "Oh, it's one of those things that rings, and you pick it up and say "Halo, 'stat you kiddo?"