You misunderstood. I was hinting at USA, Canada, UK etc. being different nations though they share the same language. Let’s change one of your sentences a little bit: “Take citizens from London,UK and Austin,TX: they still have more in common than people from two different cities in Belgium, just depending on which language is in the majority in the area.” Would this still hold? I’d say no. I am German and consider myself as European if not a world citizen. Coming from Bremen in northern Germany I have more in common with folks in Sønderborg or Groningen compared to Vienna or Zurich. More often than not Nations are arbitrary.