Jared Diamond's The Third Chimpanzee looks at different ways that humans evolved (and did not) from animals. As he says,

Human language origins constitute the most important mystery in understanding how we became uniquely human....Without language we could never have conceived and built Chartres Cathedral--or V-2 rockets. 

How did we bridge the "unbridgeable gulf" to speech, he asks. "There must once have been intermediate language-like stages linking Shakespeare's sonnets to monkey grunts." Alas, we can never hear how early people spoke.

Diamond says that vervet monkeys have the most sophisticated animal language discovered to date. They have different ways to express objects and animals they encounter, as well as common feelings.

All well and good. What I wonder is how we evolved so that we have words for things that we do not have direct first-hand experience with? Objects or animals we will never see ourselves, abstract concepts that we will not encounter, food that we ourselves will never eat. Even if other people have come up with the words to name them, the rest of us use these words and commonly agree (within the same language, or course) that a leopard is the animal with the spots and the tiger is the one with the stripes.

Language never ceases to amaze, when you really think about it.