It has more to do with the phonetic positioning of the tongue when pronouncing vowels and consonants. Head trauma can effect the cranial nerves which control the mouth, throat and tongue. The different between accents in the same language is principally due to the positioning and manipulation of these structures. So it isn't that they develop an authentic foreign accent, more that they misalign their speech producing anatomy and the misalignment produces an effect which is heard as foreign to the listener.
anonymoussarcasm t1_j699ry3 wrote
Reply to comment by Do_Better_Today in TIL about foreign accent syndrome. This is a very rare (~100 cases worldwide) but real medical condition where people abruptly begin speaking in a foreign accent following head trauma like a bad migraine, accident, or stroke. by veety
It has more to do with the phonetic positioning of the tongue when pronouncing vowels and consonants. Head trauma can effect the cranial nerves which control the mouth, throat and tongue. The different between accents in the same language is principally due to the positioning and manipulation of these structures. So it isn't that they develop an authentic foreign accent, more that they misalign their speech producing anatomy and the misalignment produces an effect which is heard as foreign to the listener.