Certainly the Thracians and the Illyrians were non-Greek speakers, but in the northwest, the peoples of Molossis (Epirot province), Orestis and Lynkestis spoke West Greek. It is also accepted that the Macedonians spoke a dialect of Greek and although they absorbed other groups into their territory, they were essentially Greeks.

"The Penguin Historical Atlas of Ancient Greece", Penguin Publishing USA, January 1997