But, in some surprising level, you have a point, only that you don't know it.
In the region i live, which is called Epirus, Slavic tribes had lived for many years, so there are plenty of words we use (and mostly, older people use) which aren't greek. They 're slavic, and i find more and more of them. There are, also, plenty of site-names that are Slavic. Some times i find whole phrases people use in Epirus, and in no other place in Greece, because they don't have much sense in our language. They are translated Slavic. I know this now, because i find them in Polish. It's very interesting, really. I can understand many things from the vocabulary in a region. For example, in most Greek western islands you can hear many Italian words.