Die polnische Sprache vor dem Ersten Weltkrieg

So half of interwar Poland was not Polish? I wonder what would have happened if World War II hadn’t occurred and Poland had kept its interwar lands in the east.
Also, what happened to the Polish people who ended up in modern Ukraine?

They count Masurian as separate but not Silesian? XD
Also, where is the Vilnius-Lida population of Poles?

Oof

In eastern parts of former Polish Commonwealth the Poles constituted an elite – nobility and inteligentsya