Eating [habits / habit] and food processing skills from around two million years ago helped humans to [dissolve / evolve] and develop language. Researchers from Harvard University say that [learning / learns] to cut meat up and using basic stone [tool / tools] to process food were [crucially / crucial] steps in our evolutionary process. The fact that we cut food up or pounded and [crashed / crushed] it meant we needed less [time / timing] for chewing. This gave our mouths more free time to [developed / develop] language and communicate. The researchers [estimates / estimate] that cutting up meat and other food saved early humans as many as 2.5 million chews per year. In contrast, the chimpanzee spends [half / halve] of its day chewing, which means it has less time to communicate. The researchers also said the [shape / shapely] of our face changed because we needed to [chew / chewy] less. Our jaws and teeth became smaller because we had [learning / learnt] to cut up food. Professor Daniel Lieberman said: "We [left / went] from having snouts and big teeth and large chewing muscles to having smaller teeth, smaller [chewed / chewing] muscles, and snoutless faces. Those changes, and others, [allowed / allowance] for the selection for speech and other [shifts / shafts] in the head, like bigger brains." Dr Lieberman chewed raw goat meat to test his [theoretic / theory] . He said: "You chew and you chew and you chew and you chew, and nothing [happens / happening] ." He added that to some extent, slicing meat into smaller pieces before chewing, "is the simplest technology of [whole / all] ".