I have come to realize that largely, in the western world, it’s most common that people speak their own language and English. It just so happens that is the same language for many people.
its because of how culturally relevant english is as a language to make others pick it up as a second language. Take for example coding, programming languages were mainly built around english monikers, so a very basic level of english understanding is helpful when doing that. Then you get to the large wall that is western, primarily American media and how its more or less it's largest export.