Additional context:
Native speakers of my mother tongue do not all understand each other due to some pretty extreme dialects. Now that I’m in Europe, I’ve noticed multiple instances of people sometimes not understand the dialect of someone from a village 10-20 km away…
In contrast, for example most American, British, and Australian people can just… understand each other like that?? I never thought much about it before but it’s pretty incredible
If anyone’s interested, languages follow similar differentiation patterns as species in evolution. Ways this occurs include: allopatric (barrier separates past equivalents), peripatric (migration), and sympatric (subcultures), etc.
It’s the same reason Matthew Rhys can do a spot-on American accent despite having an outrageous Welsh accent irl: people are more likely to grow up on the media of more mainstream languge so it becomes the lingua franca. (love Rhys to clarify)