Our English word "barbarian" can be traced back to the Ancient Greek word, (βάρβαρος Bárbaros) which meant a non-Greek; someone whose language was not Greek and someone who spoke "bar-bar," or babbled like a child (from the Greek point-of-view).  It was not originally a pejorative term; it just meant non-Greek, but by the fourth century bce it had begun to acquire a negative connotation.