There was no country macedonia before 1912, it was occupied, so was greece, by the turks, but there was a region, which had Macedonian people living on the land called Macedonia, so when nations in europe emerged, it was completely normal for us macedonians to be a country where macedonians have lived for ages, thats how nations were formed in europe right? So that was MAcedonia and it has been like that for ages. After the ottomans it was meant for MAcedonia to be one country, that didnt happen, macedonians were stabbed in the back and isntead, Bulgaria, Serbian kingdom and Greeks signed a treaty to divide Macedonia in 3 parts, every part fell in other hands, but that meant all the macedonians that were living in those parts, were suddenly all part of a new country. They were opressed and were forced to be part of the new country, new citizens. Especially Greeks took it very far with that. All Macedonians were renamed, and tortured and the exodus started.
Alexander Spoke Macedonian, unfortunatelly, that language is not preserved today, some think the third language on the rosetta stone is macedonian, some think koine is in fact macedonian. Thats not known. But he did spoke Macedonian, different than enic, he was MAcedonian, different than enes. Do you remember Demosthenes? You should study him. The enes did not see Macedonians as enes, they did not see them as equals, MAcedonians were barbarians in their eyes, they were different nation, macedonians conquered enes.
Of course Alexander spread ene culture and ene language back then, since ene language back then was the lingua Franca, back then it was the same as english is now in the western world. Also ene culture can be compared to western culture now, the dominant culture. That doesnt mean he was an ene, he wasnt.
As for Macedonians being descendants of Alexander, thats delicate situation since no nation in balkans is 100 genic, thats impossible, but, Macedonians have always been here, many characteristics, culturally, historically have all been preserved, there is indeed people in todays macedonia who have links with ancient macedonians, you can find them in southern republic of Macedonia and also in AegeanMAcedonia, today north of Greece. Whereas for the modern Greeks, they have no links to the ancient macedonians, they even dont have hardly any links to ancient enes. Since today greeks are a created ethnicity, made up of mostly Arvanites, Macedonians and Turks.