Forced assimilation of indigenous Macedonia began in 1912, when Serbian and Greek rulers declared that henceforth there would be "only Serbs to the North and only Greeks to the South", and no Macedonians anywhere.
There was even an indigenous stolen generation in Greece. In the late 1940's and early 1950's, 28 000 Macedonian children were removed from their families and sent to Eastern Europe. This seems to be a common assimilation technique employed by colonists around the world (in Australia we know this all too well).
Macedonian aboriginal land was annexed then split up in 1913 and 1919, by Greece and its Balkan allies. Greece has claimed that Macedonia has been a part of the Greek state since 2000 BC. However, Macedonians contend that they have retained their nationality and indigenous claim to land, language and culture continuously since long before that.
They consider Greece to be a neighbouring state, rather than some sort of "mother country", and claim that Greece has always regarded them as aliens, labelling them "barbarians". Therefore, Greek claims that Macedonia has always been a part of Greece are false. In fact, quite the opposite is true - in the ancient world the Greeks were subjected to Macedonia for a time. The modern Greek annexation of Aegean Macedonia (which they now call "Northern Greece") is actually an illegal occupation under today's international law.
As with any colonised indigenous nation, the Macedonians have had their language tampered with and eradicated wherever possible. This can be seen particularly in the names of people and places renamed by the invaders. For example, "Kukush" is now called "Kilkis", and many Macedonian people's names have been changed to Greek ones. For significant periods last century, Macedonian native language was actually banned. Today it is still illegal for Macedonians to use their native names in official contexts.
Today, Macedonians are still fighting for native title and indigenous customary rights. Although the European Community admits that they fulfil the requirements, and 109 countries have recognised their status as a nation, Greece still refuses to officially recognise Macedonian nationhood.