I always thought that was merely a nationalistic myth. But today, I was looking at some old maps of Balkans and found many maps like this one. It shows that half of Greece was populated by Albanians less than two centuries ago.
So, now I’m wondering whether that myth about the language vote is true?
Is this also the reason they can’t differentiate between Albanian and Greek DNA?
Thanks for any enlightment!
Edit: Changed the link of the map, as it wasn’t opening.
While it is difficult to determine the rationale behind the myth or its source without more information, I think it is safe to say that it's just a myth. It's probably an inside joke amongst some modern day Albanians because an Albanian dialect, Arvanites, was for a long time an significant language in Greece.
The Albanians had migrated to Central Greece from Albania in the Middle Age. The Arvanites, as they were called in Greek, assimilated quite well with the local population as they had converted to Greek Orthodoxy during the Byzantine era. According to the 1879 Greek census, there were 225,000 Arvanitic speakers while the entire population of Greece was only about 1.6 million. So they were a sizeable minority, even though the Hellenic State's territory only consisted of Central Greece and Peloponnese up to that point (Thessaly was annexed in 1881, Macedonia and Epirus in 1913). Of course the Arvanites were likely to know some Greek as well since that was the standard language in the Church.
At any rate, it was unlikely that there was any doubt about the choice of the official language for Greece after its Independence. An educational law in 1834 and the constitution of 1911 had already established that the Katharévousa Greek (a standard form of written Greek modified from Ancient Greek) would be the teaching language and the official language of the state and the church. For the 1911 constitution, the Greek parliament did debate whether the Katharévousa or the Demotic Greek (vernacular Greek spoken by common people) should be given the official status, but I doubt any language other than Greek was given any consideration by that point in Greek politics.
The only source that I am able to find regarding any poll is in the "Language and National Identity in Greece, 1766-1976". Mackridge (2009) mentioned that an opinion poll was carried out by Athens daily newspaper Akropolis in 1900 which asked its readers ‘what language the Greek people want'. The majority voted for Katharévousa rather than demotic. Unfortunately Mackridge didn't mention any other results from this poll.
I don't know enough to say anything on DNA, but I doubt it would be relevant to the myth.
Edit: Removed the word "Slavic" in the second paragraph.