Linguistic Archaeology

From the book Guns, Germs, and Steel which I am reading for the second time because it is so great.

p.343:

How can a linguist, studying only modern languages, figure out whether Austronesians living on Taiwan 6,000 years ago had pigs?

The solution is to reconstruct the vocabularies of vanished ancient languages by comparing vocabularies of modern languages derived from them. For instance, the words meaning "sheep" in many languages of the Indo-European language family, distributed from Ireland to India, are quite similar: "avis", "ovis", "oveja", "ovtsa", "owis", and "oi" in Sanskrit, Latin, Spanish, Russian, Greek, and Irish respectively. Comparison of the sound shifts that the various modern Indo-European languages have undergone during their histories suggests that the original form was "owis" in the ancestral Indo-European language spoken around 6,000 years ago.

Nearly 2,000 other words of their vocabulary can similarly be reconstructed, including words for "goat", "horse", "wheel", "brother", and "eye". But no Proto-Indo-European word can be reconstructed for "gun", which uses different roots in different modern Indo-European languages: "gun" in English, "fusil" in French, "ruzhyo" in Russian, and so on. That shouldn't surprise us: people 6,000 years ago couldn't possibly have had a word for guns.

Proceeding in the same way, we can compare modern Taiwanese, Phillipine, Indonesian, and Polynesian to reconstruct a Proto-Austronesian. Interestingly, the language had words for "pig", "dog", and "rice", which must therefore have been part of Proto-Austronesian culture. The language is also full of words indicating a maritime economy, such as "outrigger canoe", "sail", "giant clam", "octopus", "fish trap", and "sea turtle".