Please explain. Define first world countries? I am assuming you are talking about Europe? I would argue that many other countries (India, Australia, Canada, New Zealand, much of Africa) speak English. It is a very well known international language.
But plese do explain how some countries cultures are more compatible? We don't really have a distinct culture but a hybrid of many cultures here in the USA. Can you name a group that has not assimilated after a generation or two and took on the properties of the hybrid culture?
"First World" already has a definition. Get off your fourth point of contact & look it up, I am not your personal "Tecumseh-pedia."
Your assumptions are not my assumptions.
If you do not know the basics of culture, I can not help you. You either never were educated or were deliberately mal-educated. I will assume you are being facetious.
The USA was not a hybrid- or multi-cultural country. It was a multi-ethnic country with a single culture and a few, tenacious sub-cultures. There is a difference and that difference means that we don't
have to be ruled by a despot to keep the various immiscible cultures from going Balkan.
Any culture alien to American culture can persist if it can maintain a steady flow of new immigrants from the alien culture and keep a center of mass. Examples of such are the current Mexican / S American influx since 1964, some enclaves of Russians in the Northeast, and a few oriental hotspots in some of the major urban centers. Dearborn, Michican & the Richardson/Dallas/Garland nexus in Texas are examples of middle eastern hotspots of persistent alien cultures.