For those who don't get the subtext, people here are having a political debate disguised as a linguistic/historical debate.
OfSanguineFire is saying Romanians originate in the south and migrated to Romania (known as the "Immigrationist theory") and others are saying Romanians originate from Dacians (the Daco-Roman continuity theory).
The first theory is the favorite of Hungarian nationalists because it places them in Romania before Romanians.
Ultimately there’s not enough evidence to say with certainty either way. Insisting on one particular option, especially the less likely one, is suspicious.
I’m Romanian fwiw.
There is no evidence about such a "spreading", and especially no linguistic evidence.
We know that Proto-Albanian and Proto-Romanian have been in contact, but that gives no information about the extent of the area inhabited by speakers of Proto-Romanian in the opposite direction. The contact has existed regardless whether the area inhabited by speakers of Proto-Romanian has extended to the North of the Danube or not.
Likewise, even if we knew for sure that no Dacian word has been preserved in Romanian, that would give absolutely no information either pro or contra the immigration theory, because that has nothing to do with the Dacians, but it is about whether the Roman citizens of Dacia have continued to inhabit Dacia permanently, or not.
Therefore all known linguistic data fails to provide any kind of evidence either in favor or against the immigration theory, so such a theory should not be mentioned in a linguistic discussion, unless some new evidence is discovered.
While there exists no direct evidence either in favor or against the immigration theory, this theory is pretty much unbelievable, because it requires for Dacia to have been depopulated.
For the lowlands at the North of Danube it is plausible that they might have been seriously depopulated, especially during several centuries when many invasions have passed through them.
On the other hand, it is completely implausible that the highlands of the Carpathian mountains have ever been depopulated. Those mountains offered exceptionally good life conditions, especially for people whose main activity was raising sheep. With the exception of a very well organized state, like the Roman Empire, no distant authority could have extended its influence into the mountains, so after the Roman Empire abandoned Dacia and there no longer was any central administration, the locals were left to themselves but they had no incentive whatsoever to abandon their good lands.
There is absolutely no chance that any invasion force passing through the lowlands would have risked to lose time and supplies and people by going up into the mountains in attempts to chase some locals who did not have anything valuable enough to be worth the effort.
So for me at least, such a theory based on the premise that some beautiful mountains with everything needed by humans for a decent life and well protected against outside intruders could at any time in history remain empty, waiting for the next passer-by to settle there, is absolutely ridiculous.
As said before, this has nothing to do with linguistics, so it should not be mentioned there without a good reason.
The scenario that Romanian arrived from across the Danube does not require that the Romanian Carpathians were completely depopulated. Rather, it is possible that the region’s inhabitants first switched to Slavic – this is supported by a great deal of toponymic evidence – and then later both language shift and the arrival of other populations resulted in the extinction of the Transylvanian and Oltenian dialects of Common Slavonic in favor of Romanian and Hungarian instead.
Then, the contemporary view of the relationship between Romanian and Aromanian is not that they were mere sister dialects of Latin but split up at a much later date – they are too similar for an early split, and it appears that their first layer of Slavic loans is identical, so that means a split after the 6th century CE. The scenario that Romanian nationalists support requires believing that Aromanian results from Romanian speakers from Dacia migrating well to the southwest. That both Romanian and Aromanian came from the Central Balkans instead is viewed as vastly more likely, especially in the light of the advances in the reconstruction of early Albanian (because an array of evidence puts early Albanian in the Central Balkans, not Dacia).
> so after the Roman Empire abandoned Dacia and there no longer was any central administration, the locals were left to themselves
While I know that the story of their ancestors “left to themselves” after Rome withdrew from Dacia persists in Romanian pop culture, it never fit well with the facts. Romanian words like biserica ‘church’ suggest that Romanian’s Latin ancestor remained in contact with the rest of the Mediterranean world for a long time, because only after Constantine in the 4th century were basilica buildings used as Christian churches. Again, this would be easily explainable by an origin in the Central Balkans where those cultural contacts persisted.
