Traditional linguistic models of syntax and language processing have assumed an error-free process of language transmission. But we know that this is not the case: people often make errors in both language production and comprehension. This has important ramifications for both models of language processing and language evolution. I first show that language comprehension appears to function as a noisy channel process, in line with communication theory.  Given si, the intended sentence, and sp, the perceived sentence we propose that people maximize P(si | sp ), which is equivalent to maximizing the product of the prior P(si) and the likely noise processes P(si → sp ).  I show how this simple formulation can explain a wide range of language processing phenomena, such as people’s interpretations of simple sentences, some aphasic language comprehension effects, and the P600 in the ERP literature. Finally, I discuss how thinking of language as communication in this way can explain aspects of the origin of word order, most notably that most human languages are SOV with case-marking, or SVO without case-marking.

* This talk is part of the Special Online Talk Series: Rational Approaches in Language Science *