The distribution of word order types in the world’s languages, interpreted in terms of the putative phylogenetic tree of human languages, strongly supports the hypothesis that the original word order in the ancestral language was SOV. Furthermore, in the vast majority of known cases (excluding diffusion), the direction of change has been almost uniformly SOV > SVO and, beyond that, primarily SVO > VSO/VOS. There is also evidence that the two extremely rare word orders, OVS and OSV, derive directly from SOV.UPDATE: An MSNBC article on the paper.
These conclusions cast doubt on the hypothesis of Bickerton that human language originally organized itself in terms of SVO word order. According to Bickerton, “languages that did fail to adopt SVO must surely have died out when the strict-order languages achieved embedding and complex structure” (50). Arguments based on creole languages may be answered by pointing out that they are usually derived from SVO languages. If there ever was a competition between SVO and SOV for world supremacy, our data leave no doubt that it was the SOV group that won. However, we hasten to add that we know of no evidence that SOV, SVO, or any other word order confers any selective advantage in evolution. In any case, the supposedly “universal” character of SVO word order (51) is not supported by the data.
PNAS doi: 10.1073/pnas.1113716108
The origin and evolution of word order
Murray Gell-Mannn and Merritt Ruhlen
Recent work in comparative linguistics suggests that all, or almost all, attested human languages may derive from a single earlier language. If that is so, then this language—like nearly all extant languages—most likely had a basic ordering of the subject (S), verb (V), and object (O) in a declarative sentence of the type “the man (S) killed (V) the bear (O).” When one compares the distribution of the existing structural types with the putative phylogenetic tree of human languages, four conclusions may be drawn. (i) The word order in the ancestral language was SOV. (ii) Except for cases of diffusion, the direction of syntactic change, when it occurs, has been for the most part SOV > SVO and, beyond that, SVO > VSO/VOS with a subsequent reversion to SVO occurring occasionally. Reversion to SOV occurs only through diffusion. (iii) Diffusion, although important, is not the dominant process in the evolution of word order. (iv) The two extremely rare word orders (OVS and OSV) derive directly from SOV.