Good morning! Dr. Geary is very correct. Picture Rome as sort of like the United States in that there is no American "race," but there are Americans. While Latins, members of the Latin tribe, originally founded the city, the Romans had long since stopped using ethnicity as a basis for anything. Rather, the status of being a Roman citizen meant everything. You could be a Celt by ethnicity, but if you held Roman citizenship, carried Roman civic virtue, etc... you were, to all Romans born in Italy or otherwise, a Roman. A case in point is St. Paul, in the Bible. During his little...spat with the magister, the magister essentially announced that he, said magister, had spent a great deal of money buying his citizenship. Paul proudly retorted "but I was born free," a common phrase meaning that he was born with Roman citizenship. He was a Jew, but he was Roman, and that is all that mattered. As far as "barbarian" goes, it is originally a Greek term demeaning the languages non-Greeks spoke. They applied this to Romans too. Rome, on the other hand, used "barbarian" oddly, in the sense that not every non-Roman fell under the term. It is invented category that they tossed people into depending on individual perceptions.

Broken down, you did not need to be Italian, Latin or otherwise, to be Roman. It had to do with citizenship. A person could be born with it, like Paul, or a person could earn it, through service in the Auxilia or through donations, service, bribery etc...