I was kicked into posing this question by an article in New Scientist, 1 March page 34 about human evolution.
The suggestion in that article was that the brain development needed to make complex stone tools was the agent that led to the development of language. More complex stone tools was a need that drove brain evolution into a more complex brain, which led to having the brain ability to develop language.
Now, I see this as kinda silly. It is vaguely possible that something of the sort may have happened, but the evolution of language could have occurred in many different ways. The evidence for the idea appears to be the arrival of complex stone tools at roughly the same time as language appeared. Not that we really know when language appeared.
Paleoanthropology appears to be a science over prone to overinterpretation. I have seen, so many times, a little bit of evidence spun out into a "major new find". I say, what the hell? This is not really terribly scientific. A tooth or a vertebra becomes a new genus of pre-human.
So, are those paleoanthropologists jumping the gun? Producing new 'findings' prematurely from too little evidence. Should we be waiting until there is more, and more convincing evidence before publishing interpretations that are very likely wrong?