Sometimes I heard that L2 language learners make a surgery on their tongue in order to gain better pronunciation.
However, it this necessarily true that they achieve better pronunciation after the surgery? Or is it just a difference between the pronunciations of each language that people achieved via childhood that hinders the L2 learners from achieving the correct pronunciation?
And is there any side effect regarding the language skill, such as worse pronunciation of your L1, after the surgery?
This question is about the adult surgery.