From Alun Anderson at New Scientist, reviewing The Truth about Language: The Truth about Language What it Is and Where it Came from:
During the 19th century, Alfred Russel Wallace doubted whether natural selection could explain such a unique power. In our century, Noam Chomsky, the Massachusetts Institute of Technology academic who has dominated linguistics for 60 years, has supported a hypothesis that language and thought arose suddenly within the past 100,000 years.
In The Truth About Language, Michael Corballis rejects all such “miraculist” explanations. He lays out a plausible route by which spoken language might have evolved, not from the calls of our primate ancestors, but through stages in which a language of gesture and mime dominated.
…
When we have nothing much to do, our minds travel through past experiences, future plans and imaginary possibilities. The process of mind wandering, or daydreaming, is more remarkable than it seems. It shows our capacity to recall particular episodes from the past and project them freely into possible situations in the future, even though we are not using words, but thinking in images. More.
Sure. But when cats and pigs have nothing much to do, they are not thinking much either…
Sp here’s the problem: To the extent that the human being is thinking in a human way, he needs to think and comunicate thoughts. A language can be built up out of almost anything.* That part does not require much explanation.
It’s not the language as such that needs explaining. It’s the fact of having anything to say.
Reviewer Anderson admits:
At this point, I have doubts and must admit, as Corballis does on his final page, that he too might be writing a just-so story, despite the breadth of his evidence. Still, I much prefer a speculative account of how language might have evolved to an invocation of miracles. And, right or wrong, Corballis will make you see your own mind differently.
Actually, there is no more utility in a just-so story than in a miraculous account. But many people today feel a need to spend time, money and energy on just-so stories anyway.
See also: From Aeon: Is the study of language a science? (Noel Rude)
and
Can we talk? Language as the business end of consciousness