A physicist tackles the evolution of word order

Murray Gell-Mann was awarded the 1969 Nobel Prize in Physics for explaining the diversity of baryons and mesons in terms of more rudimentary particles, which he named quarks. If you enter his name into Google Scholar, the citation-based search engine duly returns his classic papers . In the top slot is the 1964 Physics Letters paper that earned him the Nobel.

Gell-Mann’s latest paper is not about quarks or complexity, the focus of his research for the past two decades. It’s not even about physics. In the 18 October issue of the Proceedings of the National Academy of Sciences (PNAS), you’ll find a paper by Gell-Mann and Stanford University linguist Merritt Ruhlen entitled “The origin and evolution of word order.”

By word order, Gell-Mann and Ruhlen refer to the basic sequence of subject (S), verb (V), and object (O). They classify English as SVO, as demonstrated by their example, “The man (S) killed (V) the bear (O).” Other word orders are found among the world’s 2000 or so languages. Welsh, the first language I studied in school, is VSO. The sentence about bear-killing reads “Fe laddodd (V) y dyn (S) yr arth (O).” Japanese, the last language I studied, is SOV, as in “男が (S) 熊 (O) を殺した (V).”

Gell-Mann and Ruhlen start their fascinating paper by noting that three lines of evidence—from genetics, archaeology, and linguistics—all indicate that humans suddenly started using sophisticated tools and making objects of art around 50 000 years ago. “The cause of this abrupt change has been attributed to the appearance of fully modern human language,” they write in their introduction, “and this is a plausible conjecture.”

The sudden arrival of modern language suggests a single origin, a linguistic Big Bang. Under that assumption, Gell-Mann and Ruhlen sought to identify the word order of that ancestral modern language. To find it, they looked at the word order of 2011 languages and at those languages’ likely family trees. Their conclusion: The first modern language was SOV and that languages in general evolve in the order SOV → SVO → VSO. Welsh, it seems, is more evolved than English.

Gell-Mann isn’t the first eminent physicist to study linguistics. Thomas Young (1773–1829) proved the wave nature of light, founded physiological optics, and elucidated elasticity and capillarity. He also helped to decipher the ancient Egyptian hieroglyphs on the Rosetta Stone.

What do physics and linguistics have in common that attracted Young, Gell-Mann, and perhaps others? My hunch is the quest to find order. The list of 2011 languages that Gell-Mann and Ruhlen included in their study is available on the PNAS website. The list is 45 pages long! Making sense of that diversity is a challenging and worthwhile goal.