The following is a collection of resources meant for highly advanced learners trying to bridge the gap between themselves and native speakers in Mandarin.
Table of Contents:
The following is a collection of scans and PDF related to this topic from experts who have spent decades studying this and interviewing people who have achieved such a level based on the ILR scale:
Additional books on this topic:
Books on Attaining a Near-Native Level in a Foreign Language
Clayton, an employee of Refold, has previously shared some linguistics journal articles which call into question whether fossilization even exists, or whether “nativeness” is even a valid or useful metric.
Fossilization:
Nativeness: