It is just a working theory............

.....................but there are those who believe one of the main drivers for the development of language in us humans was the ability for name calling:

     Luther had already called Henry "a pig, a dolt, and a liar."  Henry has already replied the Luther was "an ape, a drunkard, and a lousy little friar."  Gentlemen did not then confine themselves to logical arguments.  Defenders of the faith felt no constraints upon their pens or their tongues in face of opposing argument.  And as these ever more acrimonious verbal conflagrations were joined, bonfires of Luther's writings, as well as of Wyclif's increasingly archaic translations, were being lit across the land.

-Thomas Cahill, Heretics and Heroes:  How Renaissance Artists and Reformation Priests Created Our World.  The setting is circa 1523.  Luther being Martin Luther.  Henry being Henry VIII, then King of England.  Wyclif being John Wycliffe, who translated parts of the bible into vernacular English in the late 1300's.