Originally, the word "barbarian" means a person who does not speak Greek

As is the case with the "idiot" we are dealing with a gradual change of meaning of the word under the circumstances. The word "barbarian" was used by the Greeks against people from Northern Europe, whose speech was unusual Greek ear. Talk Europeans sounded to the Greeks as "bar-bar-bar" and how they came to be called travelers - barbarian. With a touch of contempt, of course, because in comparison with the enlightened Greeks, Europeans from the north and were real barbarians.

Gradually the word came up to Eastern Europe, where assimilated and turned into "Barbarian».

via factroom.ru