Very good work of excellent academic level, but also with contextual reflection. I understand that for certain work tasks or functions (such as teaching a language), having an "accent" (national, regional, local) may imply some disadvantage, as long as it cannot be controlled. Nevertheless, I believe that it is inevitable and necessary that "accents" be assimilated. Perhaps we will arrive at a language where everything is mixed or where the separations are more and more closed; it is almost a question of novel or cinema of anticipation.
Thanks for your post, @hlezama.