For me, recent computational accounts of language evolution provide a compelling rationale that cultural, as opposed to biological, evolution is fundamental in understanding the design features of language. The basis for this rests on the simple notion of language being not only a conveyor of cultural information, but also a socially learned and culturally transmitted system: that is, an individual’s linguistic knowledge is the result of observing the linguistic behaviour of others. Here, this well-attested process of language acquisition, often termed Iterated Learning, emphasises the effects of differential learnability on competing linguistic variants. Sounds, words and grammatical structures are therefore seen to be the products of selection and directed mutation. As you can see from the use of terms such as selection and mutation it’s clear we can draw many parallels between the literature on language evolution and analogous processes in biology. Indeed, Darwin himself noted such similarities in the Descent of Man. However, one aspect evolutionary linguists don’t seem to borrow is that of a null model. Is it possible that the changes we see in languages over time are just the products of processes analogous to genetic drift?
If we accept that language is not only a conveyer of cultural information, but it is itself a socially learned and culturally transmitted system, then an individual’s linguistic knowledge is the result of observing the linguistic behaviour of others. This well attested process of language acquisition is often termed Iterated Learning, and it opens up a new avenue to investigate the design features of language: that cultural, as opposed to biological, evolution is fundamental in understanding these features.
A prominent idea in linguistics is that humans have an array of specialised organs geared towards the production, reception and comprehension of language. For some features, particularly the physical capacity to produce and receive multiple vocalizations, there is ample evidence for specialisation: a descended larynx (Lieberman, 2003), thoracic breathing (MacLarnon & Hewitt, 1999), and several distinct hearing organs (Hawks, in press). Given that these features are firmly in the domain of biology, it makes intuitive sense to apply the theory of natural selection to solve the problem: humans are specially adapted to the production and reception of multiple vocalizations.