ok. there are two correct answers.
the EPL has 520 players and 334 of them are foreign including home nations outside of england. thats 64.2% of the league..meaning only 35.8% of the league consists of english players.
the EPL however has 79 players from wales, ireland, northern ireland and scotland which means the league has 255 foreign players outside of all home nations. that would mean 49% of the league is from 'overseas'.
the portuguese league has 446 players and 262 of them are not portuguese. that's 58.7% of the league.
so, depending which side of the fence you sit on regards home nation players being foreign, either the EPL or portuguese league is ranked as being the most culturally diverse.
the next nearest is Russia, where 47.9% of the league is made up of foreign imports.
in my opinion considering half the irish team is made up of englishmen with great-great-great-great irish grandparents i think portugal can be afforded the title of being the most foreign league in europe. well done to me and one other person and also the 5 people who voted for the EPL who might choose to be 'picky' with this result