In this YouTube video:
World Science Festival, “Mind Your Language: Thought, Metaphor and Imagination”. (September 30th 2021.)
The link is directly to the timestamp of the video where he says the following quote:
We use [language] for communication, of course, but it's basically an instrument of thought. [This is] a long tradition - I mentioned Galileo, but many others just assumed that language is what was sometimes called 'audible thought': it's the instrument of thought.
Now, if you think about our own language in use… almost all we do is language; construct thoughts in our mind. Sometimes we externalize them; sometimes we communicate, but that's a kind of a side-property of language.
Now we can pin that down much more precisely. When you look at the actual design and structure of language, what you find systematically is that when there are instances where there are conflicts between communicative efficiency and computational efficiency, computational efficiency always wins.
There are very simple cases like simple structural ambiguities. If I say 'flying planes can be dangerous', that’s structurally ambiguous. [Does that] mean the act of flying or the planes that fly?
Well, the point is that if you just let the rules run freely, computational efficiency [wins]… but they harm communication because [it] means [we] can't understand what somebody's saying. Do they mean to fly planes or planes that fly?
And there are many things like this. Some of them pretty serious which impede communication, but mother nature didn't care.
When evolution moves along, some change takes place [and] you get the simplest solution; simplest most elegant solution. [It] may happen to be dysfunctional, [but that's] not mother nature's problem…
That's the way - it seems - [that] language develop[ed].
What does the boldface-emphasized excerpt mean?