I say speech rather than language because speech is aconcrete behavior while language is an abstraction. In order to speak our ancestors had to evolve all the general elements of language (e.g., the ability to utter words in syntactical form) along with the specific powers of making verbal sounds. Some investigators have speculated that sign language predated speech, but even if that notion proves correct, it is speech that characterized humans when they emerged into history. The questions that concern this blog are where did that behavior come from? Why did we evolve it? When did we evolve it? How did we evolve it? (italics in the original).
Edmund Blair Bolles, blog author and humanist, goes on to describe what separates speaking from vocalizing - syntax, symbol and the ability to empathize, to put yourself in another's place. The issues here are also bound up in cognitive psychology, computation and philosophy of the mind. The key question for philosophers: how can consciousness result from computation?
Wikipedia: Tower of Babel