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Eating habits and food processing skills forfrominintoofpertoup around two million years ago helped humans to evolve and develop language. Researchers forfrominintoofpertoup Harvard University say that learning to cut meat forfrominintoofpertoup and using basic stone tools to process food were crucial steps forfrominintoofpertoup our evolutionary process. The fact that we cut food forfrominintoofpertoup or pounded and crushed it meant we needed less time forfrominintoofpertoup chewing. This gave our mouths more free time to develop language and communicate. The researchers estimate that cutting forfrominintoofpertoup meat and other food saved early humans as many as 2.5 million chews forfrominintoofpertoup year. In contrast, the chimpanzee spends half forfrominintoofpertoup its day chewing, which means it has less time to communicate.

The researchers also said the shape forfrominintoofpertoup our face changed because we needed to chew less. Our jaws and teeth became smaller because we had learnt to cut forfrominintoofpertoup food. Professor Daniel Lieberman said: "We went forfrominintoofpertoup having snouts and big teeth and large chewing muscles to having smaller teeth, smaller chewing muscles, and snoutless faces. Those changes, and others, allowed forfrominintoofpertoup the selection forfrominintoofpertoup speech and other shifts forfrominintoofpertoup the head, like bigger brains." Dr Lieberman chewed raw goat meat to test his theory. He said: "You chew and you chew and you chew and you chew, and nothing happens." He added that forfrominintoofpertoup some extent, slicing meat forfrominintoofpertoup smaller pieces before chewing, "is the simplest technology forfrominintoofpertoup all".