Prolegomena to a cognitive science of language diversity

Linguistics needs to embrace all the way down the cognitive implications of a key feature of language facts: its diversity. In this paper, we build on recent findings about the neuroscience of linguistic variation, but also on proposals by theoretical biology, to sketch some prolegomena to a future cognitive science of language diversity. We argue that the cognitive foundations of human language cannot be adequately understood without considering four dimensions of variation: the different functions performed by language, the diversity of sociolinguistic phenomena, the typological differences between human languages, and the diverse developmental paths to language. If we succeed in the cognitive examination of these four dimensions, we will not only achieve a more comprehensive understanding of how our brain processes language, but also of how language evolved, as their consideration should enable to find more evolutionary continuity between language and the cognitive abilities of other species. Overall, the approach we advocate for here is expected to result in a more accurate view of human language within the architecture of human cognition.