Speech, language and biology
By a line of reasoning seemingly first due to Gallileo , speech and language use a finite set of enitities like the alphabet to construct an infinite set of entitites such as the set of grammatically meaningful sensences in a languare. All languages allow sentences to get longer and longer with no point at which this becomes impossible. So we can say, “She’s lying.” Or “You know that she’s lying.” Or “I think that you know that she’s lying.” And so on indefinitely. Now the child may only hear one step – as in “You know that she’s lying.” But without needing to be told, learners somehow know that any number of steps are allowed, or they wouldn’t understand any numbers of steps greater than what they happen to have heard.This is now known as ‘discrete infinity’. Building on a series of publications, in 1965 Noam Chomsky proposed that the simplext explanation of discrete infinity is that there are underlying principles for language that we are born with, that are, in a species-specific way, encoded in the human genome. These principles are necessarily very simple and abstract.
The richness and complexity of human language is by the way these principles interact.
Over the last fifty years, many linguists have come to accept Chomsky’s conclusion.
No non-human has ever shown evidence of anything like discrete infinity. To this extent, humans are both unique and exceptional in the animal kingdom. But for some reason, the exceptionality of human language is strongly resisted by some.
Some geneticists take this line because of the difficulty of identifying the corresponding sequence in the DNA. But to me, the onus is on those who deny any sort of genomic explanation to provide a more plausible explanation of discrete infinity.
This is not to suggest that children are born knowing how to talk, a self-evidently absurd aunt sally sometimes peddled by those opposed to any idea of human exceptionality. The claim is just that children come to the task of learning language expecting, Exactly how this happens has been at the centre of linguistic research for the past 60 years.
A key impetus towards a biological conception of linguistics was taken in 1967 by Eric Lenneberg. There are are tell tales pointing in this direction from children with speech and language disorders. Around a third of such children have a close relative, a parent, a sibling, an uncle, aunt, or cousin, who either has or once had a similar disorder. And across a broad range of ages and disorders there are significant, well attested, and broadly agreed co-morbidities.