Albanian ethnicity is defined. Anyone who feels Albanian, speaks Albanian, has given the pledge to the flag, has at least one parent with these qualities, is Albanian.
Albanians are not a race. DNA shows that. Time ater time, different people migrated to the area mixed, learned the language and became Albanians..
That is a national identity. Just like Americans speak their language, sing a national anthem and have their flag, and say for themselves they are American, but in fact only an extremely small group of them is native American.
If they were different, why should they speak the same language? Who's language was Albanian?
In the old times there was a strong tendency to relate ethnic and linguistic identity of the tribe/people. Nowdays we know better.
For example - some group of
Outsider warriors enters a continent and gains a control over a certain small area. They rape, pillage and kill all the men and children available. Word spreads around continent about their mischief, and it gets to the
Throne Divinorus (regional interpreter of divine words), which starts calling kings, dukes and maharajas of his realm to gather the army in the name of God. Word about this army getting organized also gets to the
Outsiders leaders, and what they hear is if they don't pledge to the
Throne Divinorus they'll get crushed by the army of the seven nations. If they do pledge and promise to pay racket and send a certain number of warriors when called, they can retain their position. If they are smart, they agree to this, and they get a Crown. Neither
Outsiderian rulers, nor neighbouring kingdom, nor
Throne Divinorus care what local population feels about it, as long as they can collect gold and food from them.
If someone wants to get his children educated or working by the Court, etc. he has to give his child to the school to learn
Outsiderian. So, in a century or two, all the smart and educated men in the Kingdom end up speaking and writing in
Outsiderian. They probabaly know their native languge too, but they use it only to talk to dirty peasants and uneducated mass. If the region was not culturally strong (no books, writings, stone plates, statues, stone buildings to remember them what they are) by the time of renaissance you have a whole nation of
Outsiderians, speaking
Outsiderian, while in fact NOT being it.