A barbaros is a being that is unable to speak logos, that is unable to communicate information from oneself to another being.
One can be a barbaros, because one does not know how to use words. This is where the word barbaros comes from. The Greeks viewed those who could not talk well as saying: ba ba ba ba…
Barbaros often say the literal opposite of what they mean.
Finally one can be a barbarian, because one views as valid a proposition and its negation