Who are the Barbarians?

In Ancient & Modern Greece

In Hellenism, the distinction between Greek and non-Greek/foreigner/Xenos is very important. Since ancient times, the Greeks used two main categories for the people: "us" and "them". This is evidence of a common Greek national awareness among the politically divided ancient Greeks.
The word Barbarian ("Βάρβαροι") was used, and is still used, by the Greeks to refer to all the people who were not linguistically Hellenic (aka non-Greeks, since language was an important element of Hellenism), or had not been linguistically Hellenized. Barbarian as a word has a very negative connotation, nowadays, and it seems to have been like that since the classical era, although it wasn't originally meant to be used that way. This is because everyone who was not a Hellenophone was considered uncivilized and primitive, so the term eventually came to mean what it means today.

Longobard Barbarian warriors

It's important to note that it didn't always mean non-Greek, even in ancient Greece, and that many Greeks used it against other Greeks. For example, Prodicus of Ceos called "barbarian" the Aeolian dialect (a clearly Greek dialect), Athenian scholars called the Macedonians "barbaric", clearly for political reasons, since Athens' position as the city-leader of Hellenism was threatened by the rapidly growing Macedonian Kingdom, et cetera.

In the Roman empire

Once the Romans conquered the Hellenic world, the idea of such a distinction attracted them greatly, to a point where they decided to copy it and apply it to their own Latin civilization. Of course, since the idea was originally Greek, and since their civilization was influenced by the Greeks, they could not exclude the Greeks from the "us". So the term's meaning changed from "non-Greeks" to "non-Greeks and non-Latins".

Gaelic "barbarian" in front of Roman emperor Gaius Julius Caesar

Everyone who did not speak Greek or Latin was considered a Barbarian (which at the time also meant primitive and uncivilized). More specifically the term was used for Germanic tribes like the Goths, the Visigoths, the Longobards, as well as the Celts, the Gauls, the Berbers, and even the Thracians and the Illyrians, two Hellenic-like peoples who probably spoke languages that were similar to Greek.

In the Imperium Graecorum, medieval Greeks used the term barbarian was, again, for non-Hellenophones (even westerners), but mostly for Turks.

Today

Today the term is still used by modern Greeks to refer to non-Greeks, but usually in a joking manner, while few are the Greeks who use it with hatred towards the subject. The term may be used for all non-Greeks, no matter whether those are civilized, Europeans, whites, etc or not, although philhellenes and those who appreciated Hellenism are excluded.

Also, certain White Nationalist groups use it, but it is ironic (especially when used by Nordicists and Germans against Southern Europeans like Greeks and Italians), considering what the term actually means. I cannot help but cringe every time I see that happen.

~Michael C. Dim