The great apes are very close to us in evolutionary terms, but they don't talk. Not at all. They don't obviously do anything like talking. Some can be taught to communicate in a speech-like way using signs, but it doesn't involve actually, well, speaking.
Why the sudden leap to speech?
Recent research is beginning to suggest that it's not quite as big a leap as was previously thought.
The physical part of human speech involves opening and closing the mouth while squeezing air out through the vocal cords and past their tongues and teeth.
We tend to concentrate on the squeezing-air-past-obstacles part of speech, but what about the opening-and-closing-of-the-mouth thing?
All human speech involves opening and closing the mouth between two and seven times a second. A study of four chimpanzee populations, two wild, two captive, has found that chimps also use open-and-closing the mouth techniques at the same sort of speed.
What does this show? Well, Dr Adriano Lameira, from the Department of Psychology at the University of Warwick, says that this is strong evidence that human language has its basis in ape-language, and that the development of human speech isn't such a surprise as used to be thought.
"We found pronounced differences in rhythm between chimpanzee populations," Dr Lameira says, "suggesting that these are not the automatic and stereotypical signals so often attributed to our ape cousins.
"instead, just like humans, we should start seriously considering that individual differences, social conventions and environmental factors may play a role in how chimpanzees engage 'in conversation' with each other.
"If we continue searching, new clues will certainly reveal themselves."
And, from the study itself:
it is impossible to deduce whether this variation is attributable to intra-individual variation, context or inter-individual variation.
...which means, I think, that chimps could be discussing last night's dinner or Bonzo's body odour for all we know...
...and that, quite possibly, they could be doing it in some kind of Morse code.
Thing To Do Today: consider what you mean when you smack your lips.
And then contemplate your razor.