The term barbarian is the Latin derivative of how a Roman would describe the speech of the nothern tribes. To the romans their speech sounded like the bleating of sheep. “Ba...Ba...Ba...Ba”
Ba ba ba, ba ba rian!
Ba ba ba, ba ba rian!
Barbariaaaan!
Don’t take my laaaand!
(That’s all I got!)
I thought it had something to do with the Romans' being clean-shaven. They equated these tribes with bearded men -- hence, the word "barbe."
I also heard that the word may have originated from Greek, as well. The xenophobic Greeks equated beards with foreigners.