Moving beyond Pāṇini: causal theories in linguistics

For over 2000 years, ever since the Indian philosopher Pāṇini developed the first precise grammar of a language, linguistics has essentially been an engineering enterprise: how can we capture the rules of a language most concisely and most elegantly? This perspective persists even when the focus shifts from individual languages to larger sets of languages: traditional approaches here chiefly consist in an open-ended search for concise and elegant generalizations and correlations that are argued to hold across grammatical systems, either universally or regionally (Sprachbünde). Explanations come in only post-hoc.

Here I explore an alternative line of thinking that approaches linguistic structures as natural phenomena whose distribution in time and space can be predicted by causal theories. Such theories are rooted outside grammar: one the one hand, in what we know about the mechanisms of structure copying in language contact, and therefore in what we know about population history, and, on the other hand, in what we know about the biological conditions of language, e.g. about the neurophysiology of language processing.

I will illustrate such causal theories, their predictions and their testability with recent case studies: (a) a case study on how population movements have caused large-scale spreads of linguistic structures around the Pacific and inside Eurasia, and (b) a case study on how stable properties of the language comprehension system cause case marking system to show universal preferences in how they evolve over time (e.g. away from ergativity).