The first language humans had was gestures. There was nothing primitive about this language which flowed from people’s hands, nothing we say now that could not be said in the endless array of movements possible with the fine bones of the fingers and wrists. The gestures were complex and subtle, involving a delicacy of motion that has since been lost completely.
During the age of silence, people communicated more, not less. Basic survival demanded that the hands were almost never still, and so it was only during sleep (and sometimes not even then) that people were not saying something or other. No distinction was made between the gestures of language and the gestures of life. The labour of building a house, say, or preparing a meal was no less an expression than making the sign for I love you or I feel serious.
– Nicole Krauss, The History of Love.