The Origin of Language by Desmond Fearnley-Sander

The Origin of Language by Desmond Fearnley-Sander- When did language arise, and how? And why? If it is of value for the survival of a species, as it clearly is, then why has only one species succeeded in acquiring full-blown language? An interesting discussion of Terrence Deacon's 'The Symbolic Species: The Co-evolution of Language and the Brain'.